Added API documentation, made some refactoring

- whole API is now properly documented
- some refactoring has also been made
	- the spelling of some fields has been fixed
	- the field called "size" has been renamed to "numberOfLayers"
	- the field called "layerStillnessInMillis" has been removed and
replaced by a field called "frameRate" (a default value has also been
defined)
	- a second constructor with a extra parameter (frameRate) has been
added
	- some code shared by both constructors has been moved to a private
method called "initialize"
	
- example applications have been updated