Simplifying access to map options
Introduction of an output format model
mapsettings - addNewOutputFormat action
mapsettings - addNewOutputFormat action
Integrating an outputformat model (WIP)
mapsettings - output formats - breaking things down

- Switching from qtreeview to qlistview
- Still figuring out how to use the custom model
- ... at least it still compiles
mapsettings - outputformats WIP
MapSettings - output format - almost repaired
MapSettings - output formats

- End with new model integration
- Fixing ui aspects (activation)
Merge branch 'outputfmt-model'

Fixing also some things, still need to debug the add action of output
formats.

Conflicts:
	mapsettings.cpp
mapsettings - outputformat dialog WIP
mapsettings - format options model

Something is broken as for now, the view does not refresh after having
selected an output format. Can't figure out why yet.
mapsettings - outputformat options model (WIP)

Still cannot get it ><
mapsettings - outputformats

Still failing, giving up :-(
Mapsettings - outputformat - format options

Fixing model / refresh / sync with view, thanks @gurneyalex
mainwindow - warns the user if undostack ! empty

Instead of checking if a mapfile (potentially with no modification) is
loaded, check the undostack.
Mapsettings - some cosmetic UI changes
Mapsettings - still some cosmetic UI changes