Moved simulation components into their own package.
Added Plexer class which mux and demux will now be derived from.
Mux now derives from Plexer.
Added Demux class.
Removed configurable-input gate class for now.
ComponentType: Added decoder
SimUtil: Added decodeToInt()
Added Decoder class
Plexer: Updated to use SimUtil.decodeToInt()
Demux: nicer test output