Some minor changes in the instance model and control
Merge https://github.com/Forkk/MultiMC5

Conflicts:
	gui/mainwindow.ui
Merge https://github.com/Forkk/MultiMC5
Merge branch 'inst_rewrite' of https://github.com/Forkk/MultiMC5

Conflicts:
	data/instancemodel.cpp
Merge branch 'inst_rewrite' of https://github.com/Forkk/MultiMC5
More GCC fixes