HACKING: Add some documentation about using virtualenv with patchwork

virtualenv is super nice to isolate devevelopment from the python
packages installed in the sytem. It also allows to have parallel
configurations to run tests againsts.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
docs: Add requirements.txt for django 1.5/MySQL

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
docs: Add requirements.txt for django 1.6/MySQL

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
docs: Add requirements.txt for django 1.7/MySQL

Note: a lot of tests fail due to the removal of the long deprecated
AUTH_PROFILE_MODULE.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
settings: Make sure to use a tuple for TEMPLATE_DIRS

Django 1.7 has added a check to make sure TEMPLATE_DIRS is a tuple. We
were missing a ',', the key piece to define a tuple with one element.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>