Manipulate multiple Repositories at once with the cvmfs_server Script

This enables the following `cvmfs_server` commands to work on more than one repository at once:
* abort
* migrate
* publish
* resign
* rmfs
* snapshot
* transaction

One can simply list the repositories, that should be used like:
`cvmfs_server rmfs -f test.local test.remote`

Furthermore wildcards can be used to a certain extend like so:
`cvmfs_server snapshot *.replica`

For convenience the `cvmfs_server list` command was extended to decorate repositories currently in a transaction.

**Note:** This Pull Request contains [Named Stratum1 Replicas](https://github.com/cvmfs/cvmfs/pull/225)