Support psutil-2.0
Fix gevent dependency requirement in documentation and REQUIREMENTS.txt

gevent-1.0 has been released and it's available both on PyPI and on
Ubuntu 14.04: there's no need for instructions to install the git
development version.
Display testcases codenames in submission results for admin.
Consistently use __future__ imports in all files

Just absolute_import, print_function and unicode_literals for now, and
exclude unicode_literals from cmscontrib, cmstaskenv and cmstestsuite.
Use proper project name in copyright notices
Fix empty __init__.py files

Remove any copyright claim and add __future__ headers.
Use io.open instead of open or codecs.open