Python script for (offline) installation

[Thoemi09]

Right now, the workflow is something like this:

• clone and archive on local machine: python clone_archive_and_install.py -c -a
• copy the archive to the remote machine
• extract: tar xzf triqs_repositories
• build and install: python triqs_repositories/clone_archive_and_install.py -i -j 12

The script takes a few command line arguments with which the git clone and cmake commands can be adjusted. Additionally, one can also change the repos dict directly in the python script.