Add non-modal stash management dialog and additional menu option
"Stash snapshot..." to stash away changes prompting for a description,
which will immediately replay the stash (take snapshot and continue
working).
Add interface to IVersionControl for creating/restoring/deleting
snapshots for backup/complex undo operations (currently supported
by git only). Add test options to VCSBasePlugin.
Clean up and extend git client accordingly.

Rename IWizard::Kind --> IWizard::WizardKind, add some logic for which wizard kinds to collapse/expand.

 * Make sure we do not add duplicate or 0 (build|run)configurations
   to a project.

Reviewed-by: dt

Reviewed-by: dt

 * Fix typo in variable name
 * Make member naming more consistent
 * Use a constant for the file name postfix.

Reviewed-by: Alessandro Portale

Conflicts:
	src/plugins/bineditor/bineditorplugin.cpp
	src/plugins/coreplugin/editormanager/editormanager.cpp
	src/plugins/debugger/gdb/gdbengine.cpp
	src/plugins/debugger/watchhandler.cpp

Leading to a crash when selecting the empty entry.
The patch fixes a big memory leak with bin editors (neither the widget
nor the IFile instance was deleted, the latter leading to the empty
entry in the open editors window), and also puts a saveguard in the open
editors window, so that empty entries are not shown any more.

Task-number: QTCREATORBUG-571
Reviewed-by: Thorbjørn

Reviewed-By: thorbjorn

Remove the historical separation of "Action" and "OverridableAction".
The latter is now merged into the former.

Fix namespace usage such that all classes in shared/qml live in the
Qml namespace, and classes in QmlDesigner plugin in the QmlDesigner
namespace.

This should prevent any symbol clashes until we can finally get rid
of the file dublicates (e.g. QmlDocument).

 * Add a simple method to test whether a CMake target exists.

Reviewed-by: dt

Reviewed-by: ossi

This assumes that new Qt version entries will be put into
the System scope settings file.