Merge pull request #591 from NicoleRauch/master

Fehlermeldung beim Speicherkonflikt während der Bearbeitung einer Activity
The order of the resources is now fixed.
Rewrote the installation instructions. Added information for Windows 8 / VS 2012.
Bugfix: For multiple resources, checkboxes don't work because only checked boxes send their value to the backend. Solution: Switch to select dropdowns that send "yes" or "no" depending on which entry is chosen.
Minor cleanup of resources.