A first go at an RFX transmit node (mainly for lighting so far)
Added rfx-lights node
Deprecated rfxtrx-tx node
Started refactoring to support families of different transmitter node types
Removed rfxtrx-tx node
Added copyright headers
Extensive variable renaming to improve clarity, added comments
Added node help
Better error reporting & exception catching
Added option to set device address within the rfx-lights node, for all messages received