* update tasks are meant to be the fast ones and the ones we want to be
  sure to always do (directory creations, permissions, etc.)
* install tasks are all the really slow things, like the git repo clone
  and package installations
* Every task can by run by --tags=install,update - which is the same as
  having no tags at all.

Conflicts:

	playbooks/roles/lms/tasks/main.yml

* Move sudo:True out of each task and into the playbook, since it's a
  playbook-level variable
* Removal of a couple debian package installs from common that are also
  being installed in the role where they're needed
* Re-correction of /etc/git-identity permissions
* Other cleanups (whitespace issues, etc.)

where it can take a {{ service_variant }} param

* Create a global variable lms_source_repo to make it easy to update
  where to pull mitx from when mitx moves
* Create global variable venv_base to store location of edx virtual
  environment, defaults to /opt/edx
* Create edx virtual environment to store python modules
* Add tags to LMS and CMS tasks to make selective running and testing
  easier
* Install a long, static list of debian packages, which has been
  manually curated from other edx configurations; this probably needs
  more attention and in the future should probably be divided better
  among various roles.
* Install the list of python packages distributed with the mitx
  repository
* Install some really useful software, namely mosh and tmux

* Replace hardcoded instances of /opt/wwc with $app_base_dir, which
  defaults to /opt/wwc.
* Add tags to nginx tasks so they can be selected independently.

adding names to the nginx config playbook output

* New role for nginx, main.yml will install the nginx package
* By default create the basic version nginx config
* Add variables for nginx package version and template in group_vars/all
* Refresh apt-cache in common role