Removing non-idiomatic usage of nil

 - albeit unconvinced this improves legibility
 - going with the flow :-)
Addressed minor review nits
bool -> BOOL
(unsigned) int -> NSInteger
int -> NS(U)Integer
Switching sequence type to unsigned
isCurrentWaypointP -> hasMatchingSeq
CommsVC - instance vars -> class extension
GCSMapVC - instance vars -> class extension
MissionItemEditVC - instance vars -> class extension
Addressed minor review comments
Merge pull request #109 from fightingwalrus/idiomacy-pass

Idiomacy pass