Integrated newer cache support.
Fix code style.
Cleanup after integration of newer cache.
Update configuration of new central cache and mark deprecated method getCacheDir to be renamed to getTempDir.
Quit cache backend setup with exception if memcache server is set to be used but not available.
Improve default values and documentation of cache configuration.
Rename method getCacheDir to getTempDir and deliver path to temporary directory, provided by operating system.
Check existance and write rights of cache folder.
Use fake cache backend if cache is not enabled.
fix test target for file cache backend
Merge branch 'feature/cache' into develop