Use vagrant-vbguest plugin to sync VirtualBox Guest Editions versions

Wiki will need to be updated to reflect this addition

Added script to auto install vagrant-vbguest if it's needed
Make LC_ALL default to 'en_US.UTF-8'.

The LC_ALL environment variable is set to en_US in /etc/default/locale
in the precise32 vagrant box, see:

https://github.com/mitchellh/vagrant/issues/1188

When running the python unit tests in the devstack machine, several of the
tests fail with a UnicodeEncodeError when trying to create folders with names
that contain non-ascii characters.

Explicitly setting LC_ALL to en_US.UTF-8 before running the tests fixes this issue,
but it would be nice if the box was set up with the en_US.UTF-8 locale by default.
squashing commits

devstack to not use pre_supervisor

typo error

Taking out edxapp_pypi_local_mirror, replacing with COMMON_PYPI_MIRROR_URL

Adding back - for white space

Conflicts:
	playbooks/roles/edxapp/tasks/deploy.yml
taking out paver task for now
Merge pull request #971 from edx/han/devpi

Using PyPi URL instead of DevPi
Merge pull request #968 from mtyaka/lc-all-utf8

Make LC_ALL default to 'en_US.UTF-8'.
adding xqueue to commoncluster and warning about reboot
Merge pull request #976 from edx/jarv/add-xqueue-to-common-cluster

adding xqueue to commoncluster and warning about reboot
Use COMMON_PYPI_MIRROR_URL in discern,ora,edx_ansible,supervisor,xqueue,xserver

Make it easier to use a local pypi mirror in the roles listed above
Add my name to AUTHORS, Wang Peifeng <pku9104038@hotmail.com>
Merge pull request #977 from edx/feanil/local_pypi

Feanil/local pypi
Don't use common_pypi mirror for devpi.
Merge pull request #978 from edx/feanil/local_pypi

Don't use common_pypi mirror for devpi.
Removing auto install script
Whitespace
Merge pull request #962 from edx/han/Vagrantfile

Use vagrant-vbguest plugin to sync VirtualBox Guest Editions versions
Fix travis.
Merge pull request #980 from edx/feanil/fix_travis

Fix travis.
Move xqueue to the common cluster.
Remove parameter entirely.