graphicsframework

* Activated error checking via conditional calls to failure()
** We just exit in case of an error and do not use return value checks anymore (crude but effective)
** Both, stderr and stdout are now always (for non-trivial commands) redirected to the logfile to ensure nice and comprehensible output
* Added "svn revert" right before "svn update" to make sure all files (incl. patched ones) are updated
* Removing target source tree folder when using tarball download (e.g. freetype2)
* Refactored tree preparations
* Improved logging
* Renamed "setup" to "build"