avoid div/zero error
Merge branch 'master' into feature/575_freq_part2
Merge branch 'master' into feature/575_freq_part2
Issue #855 - Let tab key cycle through drag modes
Merge pull request #872 from pecko/issue855

Issue #855 - Let tab key cycle through drag modes
Include guidance to cover cycling through drag modes
Merge pull request #877 from debrief/issue855_tab_guidance

Include guidance to cover cycling through drag modes
 In Track Tote, put "Show Units" in toolbar #848
Merge pull request #878 from kumarbabu/Issue848_units

 In Track Tote, put "Show Units" in toolbar #848
increment versions of all plugins, features and products following
license update.
Merge pull request #880 from debrief/releases/20141021

increment versions of all plugins following license update.
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