* Changed Shortest Path Follower criteria to use geodesic distance

* Fixed bug with uneven splits for dataset
* Fixed check if test data was loaded for CI

This PR seeks to bring habitat-API inline with this. StaticPointGoalSensor is now just a PointGoalSensor and the old PointGoalSensor is now a PointGoalWithGPSCompassSensor. There are also now explicit GPS and Compass sensors, such that you can fairly easily compute PointGoalWithGPSCompassSensor given [PointGoalSensor, GPSSensor, CompassSensor].
The PointGoal* sensors now also include {2d, 3d} x {Cartesian, Polar} support.

* before doc

* use iter getter instead of as a dataset attr

* fix docstrings

* changes according to comment

* fix long var name

* use default value in next

* fix baseline test import and docstring

* lr scheduler and tb writer

* refactor config

* More Env typing fixes

* Move log_file config entry

* fix tb-related VectorEnv del bug

* change config entries to list

* fix env class retrieval

* change default opts to empty list

* changes according to comments

* Make fog-of-war darker and make that value changeable

* Add fog-of-war to topdown map

Make env access episode through iterator

Update Habitat-API to allow for no rendering sensors

* made simulator actions iterable

* Add checkpoint progress tracking for evalute_ppo. Now when specified with a checkpoint directory,
* Evaluate_ppo will evaluate checkpoints in chronological order, and constantly check for new checkpoint.
* Add tensorboard visualization to both train_ppo and evaluate_ppo
* Add video generation for navigation episode evaluation. Generated videos can be either saved locally or visualized through tensorboard.
* Add shortest path visualization

Updated version to 0.1.2

SimulatorActions is no longer an enum. It is an extendable singleton. It allows you to extend the action space but it is quite strict about it. Actions cannot be put on different ints, actions cannot be remove.
There is now a registry for action space configurations.

Fix docs typo: step() -> act()

Added description how to use config system, fixed missing copyright headers, improved example and isort CI (#125)

* Added description how to use config system related to #20.
* Added missing copyright headers
* Improve registry example to be cleaner
* Adde habitat_sim as first party lib to isort CI setup

* Generalize PPO with both PointNav goal sensors
* generalize simple agents and fix lint
* Removed dataset specific nodes

* check scene paths, minor fix in pointnav generator

Fixes and upgrades the collision logic.

Adds documentation for habitat-api, to view the docs follow instructions in docs/README.md and view the html files from the build folder.

- add config option NUM_SAMPLE_EPISODE, with default value -1 that
indicates use all episodes. When set value to non-negative integer,
pointna_dataset will sample the specified number of episodes.
- fix the functionality of merging multiple config files. Now can specify
more than one config file like this
	--task-config "a.yaml" "b.yaml"

Our registry pattern is far from idea and thus we haven't used it consistent. This PR aims to resolve this by copying the registry pattern used in Pythia (as it is much nicer) and then registering all current measures and sensors and using the register to query for those instead of getattr as this is a more clearly extendable pattern (as compared to monkey patching).

Utility method for getting the current observation. Sometimes you want the observation without having to make a step/reset call for whatever reason.

* Builds and installs habitat-sim with python setup.py install
* Added pytorch installation and running habitat baseline test in prediction mode. That maybe too much of testing, but decided to keep it for now.
* Have ideas how to speed up and parallelize jobs. Will follow up in next PRs.
* Run isort and black on whole code to make it happy.
* Includes parallelization of installation steps and use files as flags that step is finished. CircleCI has no good way to parallelize steps and have dependencies one the same machine.
* Cache is used to save conda dependencies installed and build simulator based on commit SHA.

use attrs for defining things like Episodes and Goals as inheritance works beautifully and classes get a lot of helpful methods for free.

Changing action space names to say what they actually do, adding the look up and look down actions.

  * Add `test_static_pointgoal_senosr()` in `test/test_sensor.py`
  * Fix overriden configs in `test_sensors.py` (now using default config)
  * Change default config to include static pointgoal sensor
  * Fix `StaticPointGoalSensor._get_sensor_type()` to return `PATH`

Close paused workers

* Added episode generation code for PointGoal task.
* Removed usage of internal methods, added island_radius method to HabitatSim
* Added generator test with shortest path proper test and episode serialization testing.
* Fixed formatting issues and unused imports across the codebase.
* Added editor config style formatter properties.

* Fixed render function in vector environment

* Update test_habitat_env.py

* Add message to assert

Config system improvements: compositional config, added scenes_dir, removed config_dir, fixed eqa test (#77)

* Added scenes_dir parameter to Config to have no requirement of data symlink or data directory in working directory. scenes_dir will be used as prefix for scene_id during episodes dataset loading.
* Added overwriting options argument to get_config that unblocks parameter sweeping and experimentation capabilities from command line
* config_file path can be comma separated list of configs that will be merged in exact order. That will help to use separate configs for dataset specification and sensors setups. String with commas was chosen because that make it easy to pass list of configs as script argument.
* To make habitat-api easier to as package we decided to get rid of forcing loading of configs from config_dir param
* fixed unit test caused by latest habitat-sim update
* Added support of config list, corrected scene_path, added overwriting options, added EQA dataset changes, adopted quaternion suggestion
* Fixed headers

* added conversion of matrix map to color picture
* added example

* Vector env utility functions, added general call command