several code improvements
some caching improvements
some caching improvements #2
set version to 0.5.0-beta4
set version to 0.5.1
fix for rebuild cache function
eventplan fix
error handling when client time settings are wrong
fix for action 'Show Information'
remove pprint :D
set version to 0.5.2
optimize imports
Merge remote-tracking branch 'upstream/master'

Conflicts:
	resources/language/German/strings.xml