This splits up the edit and active settings. Let people try it and
report usability problems. I'm not 100% convinced of the layout either.

Reviewed-by: Trustme

Task-number: 258468

Things you mustn't do:
1) end an enum with a comma

2) #include <cxxxx> and not use std::

3) use anonymous structures

All three things are invalid C++. Anonymous structures inside
anonymous unions are allowed by GCC, but that doesn't mean it's valid.

Snapshot::dependsOn(fn) returns the files in the snapshot that depends on fn.

Add missing Q_OBJECTS where tr() was used.

This removes the all hard dependencies to and from welcome screen,
except the one to the core plugin. More in detail:

- Add IWelcomePage to add a tab to the welcome screen
- Move tabs in the modules where they belong
- Enables QHelpManager to open help fullscreen and contextually
- "Getting Started" moves to Qt4ProjectManager
- Projects & Sessions (aka "Develop") moves to ProjectExplorer
- "Community" remains in the welcome plugin for simplicity

Move WelcomeModeTreeWidget to utils, add d-ptr.

Thiago changed the way buildkeys are parsed, thus to reintroduce the
patched plugin loader, the changes to the build parser must be ported to
the patched plugin loader. Or the patches to make the plugin loader
faster to the current state of the qt plugin loader.

Done-with: danimo

Patch based on the analysis by Grigory Zagorodnev.

Task-number: 253974

Add some functionality needed for CVS.

Reviewed by Thorbjørn Lindeijer