Fixed non-portable use of '%u' in snprintf() in Rx::ValidateCmd(). Fixed other non-portable uses of snprint() and added more port-specific defines in Clide-Port.h. Removed RX code from Clide::Tx class. Added double braces around initialisers for two Rx::Run() variables. Changed optint to (optint - 1) when printing option which caused '?' to be returned from getopt_long(). Added unit tests for quotes and negative numbers.