[Feature #811] Only 1 Instance of OpenCS is Allowed

If another instance of OpenCS is started, then it will terminate. This
is done by creating a QLocalServer with a unique ID. If another
QLocalServer with the same ID attempts to be opened, then the creation
of the QLocalServer will fail and the application will terminate.
[Feature #881] Raise OpenCS New Window After Re-execution

The OpenCS startup window of the existing exist is raised when trying to
start a new instance. This is done by the new instance connection to the
existing instance's QLocalServer. Once the connection is established the
existing instance raises the startup window.
[Feature #881] Code Formatting

Code formatted to the OpenMW policy.