This reverts commit 5234c775 and 21065291.

- Enable qmlprojectplugin even if Qml support is disabled.
- But disable its wizards in that case.
- Disable the Qml file wizard if the support is off.

Reviewed-by: Kai Koehne

To get QML functionality back, export QTCREATOR_WITH_QML before
running qmake

Reviewed-by: Kai Koehne

VCSBase in turn already depends on TextEditor.
Task-number: QTCREATORBUG-1103

Should have been part of 9aaf2ec8

Reviewed-by: dt
Reviewed: erikv, con

Users also can now explicitly set the path to the private
header files by passing "QT_PRIVATE_HEADERS=$PATH" to qmake,
or force qmake to ignore the plugins by passing in an invalid
/empty path.

Reviewed-by: con

All files have been renamed from Qml to QDeclarative.
Registration of types is now done in an initializer method.

The new QML Inspector depends on DebuggerPlugin. Also added a dropdown menu into
the debugger toolbar from which the user can select the used debugging
language, e.g. C++ or QML.

Old format is still available as a fallback.

Otherwise parallel builds might fail

This adds a new "Design" mode that can be used to manipulate qml files
in a visual way. It will only get build if you have the declarativeui
module in Qt.

This is a squashed import from the Bauhaus project. Share & enjoy :)

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

It was trying to build the ProjectExplorer before the Welcome mode,
and failing.

Reviewed-by: Thorbjørn Lindeijer

Missing dependency in plugins.pro, sometimes breaks multi-process build.

This check is no longer needed since the necessary private headers are
now part of Qt Creator.

Reviewed-by: Friedemann