Automatically adapt kate indentation-mode to formatter settings and more

-Add an option whether to adapt kate indentation mode to the source formatter configuration.
-Send commands to kate through the command interface.
-Update kate modelines while reformatting even if "Add Modeline" option is inactive.
-Fix a slight newline-bug of the "format line" feature.
-Fix a bug in the source formatter settings dialog which led to
the checkbox option changes sometimes being ignored.