Make the menu "Perspectives" menu options order and naming match the main tab
Fix Perspective->Simulation menu option

There were two separate actions for the simulation view, leading to
strange behaviour when it was selected.
Make all the view actions checkable
Hide Mavgen, GoogleEarth, and 3D local view menu options when support is not compiled in
Hide the software and terminal action menu if not in CUSTOM_MODE_APM
Enable the terminal view for everyone - it's not specific to APM
We must save a separate config file for each custom mode

Because the indexes into the stackedwidget are all wrong
Hide the update firmware menu option since the code for it is completely commented out
Merge pull request #688 from johnflux/master

Master