Merge pull request #136 from DenisKnoepfle/master

Big refactoring of ExtensionItem and custom handlers
Fix small bugs concerning ExtensionItem

Change-Id: I15bf98aafa6432d2b26a16a3de389191f9d5cfb6
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>
Add "not available" image if resource not found

Fixed initial display position of resource shell.

Change-Id: I631db1a9965681b40eaa7bc8dc5ea470fbc51861
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>
Implement reveal action after job is finished

Change-Id: Ic4281f1ea8140402c934123e1bb2a6a3f4491bef
Signed-off-by: Denis Knoepfle <denis.knoepfle@sap.com>