If no/wrong image is definied for NPCTalk mission, the image element is made invisible

-NPCTalk class catches the IllegalArgumentExceptions thrown by GeoQuestApp.loadBitmap() and MissionActivity.getMissionAttribute() and makes the image element invisible
-not tested with robolectric yet!
Merge remote-tracking branch 'origin/master'
Refactoring Menu Setup mostly into class MenuMaker
launch config for Robolectric Tests
Merge remote-tracking branch 'origin/History'
Neighbors of TransitionItem can now be computed
In case test breaks its better to see missing elements first
Merge remote-tracking branch 'origin/master' into History