Survey (Grid) Imperial Support, + random clean-up.

Still have to set altitude in meters, although it will add WP's in feet.
Merge pull request #565 from tristannovak/master

Survey (Grid) Imperial Support, + random clean-up. Issue: #541
update TC translation
delete .zh-TW.resx to keep TS clean.
update for Traditional Chinese translation
Add zh-TW translation file
update Traditional Chinese translation
Merge branch 'master' of https://github.com/MPHant/MissionPlannerFork
Merge branch 'TC_branch'