change mnea time string parsing
  - reduce cpu overhead caused by floating point arithmetic
  - avoid possible rounding artefact
add option for revert NMEA parse Change for time.
Merge branch 'NMEAtime' of git://github.com/brunotl/LK8000 into new
Merge branch 'BetterTaskPitorials' of git://github.com/AlphaLima/LK8000 into new