Tentative polling added
Flush all data before attempting to read
Use a for loop, rather than some strange generator syntax
Use correct settings for the gps serial connection
Use a carriage return at the end of gps commands
added getting RMC line,
Switched tabulators to 4*spaces (could that cause the checksum problem?)
Merge branch 'polled-gps' of github.com:AberSailbot/sailbot2013 into polled-gps
Removed more tabs
Added _get_line method

Refactored gga and rmc getters to use it
Merge branch 'polled-gps'