This reverts commit f8c50013.

The Qt4ProjectManager now uses metacalls to inform the QmlJSModelManager
about the project data.

Done-with: hjk

Introduced new Creator-specific qmake variable QML_IMPORT_PATH that
lists the import paths required by the QmlJS engine.

Done-with: Alessandro Portale

 - lessens open file handles
 - improves help plugin startup further

Task-number: QTCREATORBUG-337
Reviewed-by: ck

Move dependencies up.

creating a debug run configuration. Import the debugger
into Qt4ProjectManager.

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

This means, creating a new project, we immediately have completion for
the ui file. Also adding stuff to the ui file now changes the codemodel
immediately.

Yet todo, are tests under windows and suppressing a warning if the form
contains a toplevel spacer.