To allow the vagrant user to create the /opt/edx/[log|data|db] folders

Compatibility with the Filesystem Hierarchy Standard: http://www.pathname.com/fhs/

Cf README, this adds support to install and setup a dev instance through
Vagrant. The Vagrantfile at the root handles the vagrant commands like
`vagrant up`.

Provisioning is done by the shell script `vagrant-provisionning.sh`,
which is a light wrapper around the `create-dev-setup.sh` which does
most of the job using the standard process, but limiting possible
side-effect by ensuring the environment on which the install is
performed is clean.

Based on an Ubuntu precise 12.04 LTS.

Since the output is passed through tee, when the django admin asks the
user if he would like to create a super user account, it blocks the
install, without even showing the question.

Disabled interactivity for syncdb.

Added options to make the output of `apt-get` and `mkvirtualenv`
friendlier to getting logged. This allows to be more easily recorded in
log files or when the install is performed through utilities - like
Vagrant.

The options passed to curl were not always the same - added logging of
error (-S) everywhere (was only used for Mac before) and made it quiet
in the rare few cases where it wasn't yet (-s).

The script used to download the latest version of ruby through rvm, then
later on install the one used by the project. Now we directly download
the version of the project when rvm is installed.

Added several options to the `create-dev-env.sh` script to improve its
ability to be used by another script:

* -y -- non interactive mode (no prompt, proceed immediately)
* -n -- do not attempt to pull edx-platform
* -q -- be more quiet (removes info at beginning & end)

This will be used, in particular, for Vagrant provisioning.

Before executing a command, for security reasons `sudo` clears the
environment, so the value of DEBIAN_FRONTEND was never passed to
apt-get. This was causing the mysql packqge to still prompt for
a value interactively.

Use super for calling parent __init__ methods

Refactor rake tasks for pylint/pep8

PDF textbooks in Studio

clarify LICENSE

Previously, for a textbook with only one chapter, we allowed that chapter to
not have a title -- under the assumption that it would be shown as a monolithic
textbook, instead of a chaptered textbook. However, the UI doesn't support that
idea, the code was getting a bit messy, and there was no real benefit to the idea
of not having to specify a chapter title. This commit removes that special case,
and ensures that all textbook chapters must have a name and an asset path.

They are the defaults now

But only slightly. Sorry Christina.