Replace used combo cell editor by custom variant

Now using the native combo box instead of the CCombo to get rid of
unnecessary white space in the item list of the combo box. Also clicking
on an item with the mouse automatically deactivates the editing properly
now (so that the dirty state of the editor page is shown correctly,
earlier it was necessary to make the control lose focus first or hit
enter to apply the value).

Change-Id: I2231fa7fa563891e8cdfc9a7ed1197b53caf4506
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>
Add FileManager to handle writing of config files

The FileManager will be used by the service layer to create the
configuration files for DS based on the data received within a
JobDescription object.

Change-Id: I61efeba8df69bbcaf388284b1a501ba6ea7c4374
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>
Merge pull request #127 from DenisKnoepfle/master

Replace combo box cell editor and preparation for #118