* 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`

* 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.

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

* Made simple agents suitable for challenge submissions.

* Addressed the comments, chaned flag names, switched to benchmark

* Removed .swp file, added swp to gitignore.

* Compatability with habitat-sim#6

* Fix formatting

* Just use the quats to rotate thing

* Burn in looks good

* Fixup newly merged code wrt. this PR

* Nits

* Fixup quaternion usage

* Add TODO

Added collision and proximity measurements; Use is_navigable for a more robust check for top-down map

Benchmark and challenge implementations; PPO agents, Random, ForwardOnly, GoalFollower agents; High resolution top down map and bird-eye visualizations; Collisions measure introduced; SPL success criteria fix; Added deleter that closes subprocesses