Summary of bug description
   * actual behaviour: If you klick "open file", the directory is not saved and you always start at the same directory
   * expected behaviour: The directory should be saved an if you klick "open file" again you should start at the same place
 
Cause of the bug
this feature was not implemented yet

Proposed solution
add / modificate a few methods in the class QmitkFileOpenAction

Affected classes
QmitkFileOpenAction

How will the bugfix get tested?
I didn't find existing tests for the class QmitkFileOpenAction. The class is part of the gui so we need manual tests as long as there is no test-framework for gui tests.