Added support for ISY994 Insteon and X10 Controller (and other updates)

1) Upped the requirement for PyISY to version 1.0.2. 2) Omitted isy994 components from coveralls tests because it requires an external controller.

1) Added visibility documentation to the CONTRIBUTING.md documentation. 2) Pylint fixes to homeassistant/helpers/entity.py

Moved card visibility logic out of the Entity class and into a VisibilityABC. Then made the Group class inherit the VisibilityABC. No duplication of code now. This is definitely better.

1) Merged with mainline dev branch. 2) Removed assumption in homeassistant/__init__.py that states are visible if not specified. This assumption is intrinsic in the JavaScript. 3) Recompiled frontend to assist merge.

simplistic Modbus implementation

Update CONTRIBUTING.md

Updated icon list url

Added a script for listing entities in running Home Assistant server. Usefule for creating visibility list in configuration file.

1) Performed many pylint and flake8 fixes to clean up isy994 integration and hidden entities addition. 2) Added necessary code to allow groups to also be hidden. 3) Made most of the weather data from the isy994 component be hidden by default.

1) Added basic back-end framework for supporting hidden entities. 2) Enabled hidden suggestions in the isy994 component entities.

Added hidden_string and sensor_string properties to the isy994 configuration to allow nodes to be hidden and to be handled as sensors. Implimented the sensor_string. Any node name that contains the sensor_string in its name will be treated as a sensor instead of a switch or light. The hidden_string will be implimented later.

Removed interactivity on the small more-info version of the line graphs that was causing scrollbars issues

Removed interactivity from small view of line charts which was causing scrollbar issues on more-info card

Adds basic support for Transmission torrent client as a sensor.