Remember Display Preferences for Main Screen

[CoryFoy]

Is your feature request related to a problem? Please describe. The Main Screen of TAK Tracker allows for different measurement units to be selected (m/s, mph, Lat/Lon, MGRS, etc). However upon closing and reopening the app these selections reset to the default

Describe the solution you'd like Remember the user's preferences for any screen unit measurement changes

Additional context This will most likely be critical once MGRS support is in place