Details:  access PluginManager::instance() instead

    RevBy:    dt
    Details:  also clean up the class interface a bit

cursor when in ex mode.

    Details:  also provide an inactive implementaion for ','

    Details:  the installHandler() overload was missing an implementation

Details:  returns the argument if it is absolute and already exists.

Details:  Add a dialog asking for command line options and build
directory. This dialog pops up if you don't have a .user file. Note,
though that it also pops up if there is already a in source build.
(The build directory lineedit should be read only then.)
The cmake button in that dialog and the output pane need more polish to
make them better. With those changes you can now build and run marble
from Qt Creator. (For marble you need to pass a few options to cmake.)

Also add a configuration page to the Tools/Options dialog, where you can
specify the cmake executable path.

And add a class which runs cmake in the background to find out which
version and wheter that cmake version has Qt Creator generator. (Which I
did begin to write.)

Details:  Little tweak improves readeability for the cmake support,
since that currently names the runconfigurations according to their
full path. Which is suboptimal and will surely change.
But adjusting to contents is better regardless.

    Details:  exclusive motions seem to require extra thought

Task:     Found by Sebastian while adjusting Bitrock
RevBy:    Sebastian
AutoTest: None
Details:  -