Task-number: QTCREATORBUG-1040

See c722282c.

Use a lowercase .qml file found in project tree if no current file is
selected. This way we don't have to disable run controls if there are
some files to execute.

Reviewed-by: kkoehne

Reviewed-by: dt

Task-number: BAUHAUS-396
Reviewed-by: dt

Reviewed-By: con

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

Reviewed-by: Kai Koehne

Putting every class in it's own files + avoid "using namespace"