Need to fix bug in time duration with posix time and deal with day
offsets in the code. Something seems off with day duration for long
periods of time.
Adding unit test for system-parameters block, testing string decoding
logic for GLONASS GNAV messages. Bug fixes the code after several errors
were detected while debugging
Adding code for navigation message computation for GLONASS GNAV code.
Continues to fix the almanac position computation and fixes bugs in code
due to compilation errors, coding style and Doxygen documentation
