Bugfix for bare "Local Path" repositories

If a project is configured as hosted in "Local Path" and the repository is bare, the build process
does not create a folder to contain the working tree, causing the tar extraction to fail This is fixed by
adding a mkdir-command.

The configuration file was never loaded for bare repositories, causing every build to fail (Builder::$config
was null and array_key_exists failed in Builder.php). Calling handleConfig after extracting the repository fixed the problem.

Tested on Debian 7.1 using Apache 2 (with and without phpci.yml-file).