Add radio support. Build separate executables for TeleMetrum and the TI dongle

Ok, way too big a patch, but things were in rough shape.
This patch adds support for the radio, both transmit and receive.
Then, because I could no longer run the TeleMetrum code on the TI
dongle, I ended up building a separate image for the TI board, which
involved creating a mechanism for having multiple command sets and splitting
code for different functions into different files.