avoid div/zero error
Merge branch 'master' into feature/575_freq_part2
Merge branch 'master' into feature/575_freq_part2
Issue #853 - Refactor top menu - solution 2
hide two more Menu actions.
Remove the Project menu
Merge pull request #886 from pecko/issue853a

Issue #853 - Refactor top menu - solution 2
correct the sound speed label (be more explicit)
correctly convert between ms & kts
comment the data types
allow the user to specify doppler calc in m/sec
Merge pull request #889 from debrief/issue882_sound_speed

Issue882 sound speed
Merge branch 'master' into feature/575_freq_part2
Merge pull request #890 from debrief/feature/575_freq_part2

Minor fix, pull it in.
introduce extra method, to indicate that "any" parameter has been changed
if any SATC change happens, mark the plot as dirty
also track changes in the solver, not just the contributions
Merge pull request #892 from debrief/891_dirty_plot

891 dirty plot