Update gradle version
Add image previews for menus
Build script improvements

 * Moved buildscript dependencies to main build file
 * Increased android gradle tools version
Increased app version
Improved build files
Increased support library version
Removed some commented out code
Extracted sort order implementation and changed sort order
Adding mock code for unset STW_URL
MockRestWrapper is not an EBean anymore
Merge branch 'cbruegg-master' into pr36

Conflicts:
	app/build.gradle
	build.gradle
	gradle/wrapper/gradle-wrapper.properties
Deleted unused resource file
Reordered entries and added ScrollView
Added developer list to about
Fixed ion version, removed method breaking travis build
Merge pull request #37 from ironjan/pr36

Merged #36 with some additional changes
Version bump
Merge branch 'develop'
Merge branch 'master' of github.com:ironjan/MensaUPB