Support opening .qml/.qmlproject files with creator from 3D Studio UI

It should be possible to use creator to open and edit .qml and .qmlproject files that are part of the presentation project in studio. 

• How to do this in UI? Doubleclicking on the file in project view seems an intuitive way. Check with Soili.
• Other file types that need external editors should also support this.
• Opening files of most types can simply open whatever default application the operating system has for that file type.
• .qml/.qmlproject may well work the same, but needs to be checked. See also notes below.

Notes from Thomas Hartmann on this issue:

Qt Creator does support a special QML only project file format with the ending .qmlproject.
The project file format is pure QML and self-explanatory.
You can create such a project by using the wizard in "Other Project" Qt Quick UI Prototype from Qt Creator.
The project will be run by qmlscene and you can define import paths. For the files
itself, you can use wildcards.

Now if you want to open a specific QML file in Qt Creator you can do the following:
call "<pathToCreator>/bin/QtCreator -client <pathToProject>/myproject.qmlproject"
This will open the myproject.qmlproject in Qt Creator. The "-client" argument ensures that no new instance
of Qt Creator is opened. If Qt Creator is already running then this instance is used.
Then you can call "<path>/bin/QtCreator -client <pathToProject>/myFile.qml"
to open the specific QML file you want to open.

You can always open the project first. If the project is already opened Qt Creator will simply do nothing.

This way a simple file based integration can be achieved easily.