Modlist profile saving and loading

Profiles are meant to manage active mod lists for users.
For example: I have two playthroughs (one realistic, one experimental), and I use different mods for them.
I don't want to switch on/off each mod manually every time, hence profiles can be created to load/save a list of active mods.

You can now go to Settings > Profiles in the menu bar to open the Profiles dialog.
There you can create a new profile based on an old one.
You can also choose which profile to use.
These settings are stored (using the configuration class) to GUIConfig.xml.

Upon loading a different profile, the Changeset is modified and can then be applied in the Changeset tab.

I have tested the functionality myself - but more testing will be needed to find possible bugs that I missed.