* Fix feed update via git.
* Add support for bzr and hg.
* Proper escaping of command line arguments handed to system.
* Reduced code duplication.

Patch by Justus Winter

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@13782 3c298f89-4303-0410-b956-a3cf2f4a3e73