Use right fields for georeferencing pictures.

Uses the GPS alt as the georeference altitude.
Disable SignAssembly in a couple of files so it's easier to compile.
Merge pull request #34 from arthurbenemann/georef2

Fix georeference code
Mission Planner 1.2.49
change update location
update georefpage
add compass rotation
update ac geofence
add refresh part.
Merge branch 'master' of https://github.com/diydrones/MissionPlanner

Conflicts:
	georefimage.cs