Fix CLI file extension handling, improve error trapping

Conflicts:
	Plugins/org.mitk.gui.qt.cmdlinemodules/src/internal/QmitkCmdLineModuleProgressWidget.cpp
Integrate Sascha's changes re: const correctness and fileName.isEmpty()
Use QTemporaryFile when running CLI
Rename QmitkCmdLineModuleProgressWidget to QmitkCmdLineModuleRunner
Merge branch 'bug-18067-cli-file-extensions-not-parsed-correctly'