Add external transmit support to the C library.
Add the functions from the last commit to the header file.
Add external transmit support to the C++ library.
Add external transmit support to the .NET library.
Remove some Thales code that shouldn't be in main line.
Fix a doxygen error with the new external_transmit code.
Simplify utils case statements.
Fix a potential bug preventing setting rs485 on the 335 cards.
Switch to using the LINE_CONTROL macro in the driver.