Changed RfxCom.prototype.enable() to use sendMessage() instead of using serialport.write() directly.
Removed unused buffer variable
Further refactoring of RfxCom.prototype.enable
Protocols can now be a single protocol.
Tests now pass again.
Added a test for enabling a single protocol
Merge pull request #17 from njh/enable-sendmessage

Changed RfxCom.prototype.enable() to use sendMessage()