[BREAKING] Reworked base Things

[s-kostyuk]

Reworked a set of base Thing types

• moved all base (abstract) Thing classes to the new package;
• removed IsActive capability for AbsActuator;
• a list of supported commands is now filled automatically by CommandsFiller metaclass;
• added a lot of new base Thing types, according to #109 to base docs and code;
• renamed Switch to AbsOnOff and Slider to AbsOpenClosed;
• reworked base Player;
• updated Dummy integration to use new class names;
• added a new private field called "_type" to all end classes; will be used in future.

Closes #109