Now the install happens in the current directory, with logs in a 'logs'
subdirectory.

Other improvements: curl now fails if the Vagrantfile can't be
downloaded, because the RELEASE value is invalid.  Curl also doesn't
print as large a progress bar.  The script fails early if there's no
RELEASE specified.

(cherry picked from commit 66a25250)

Pin the demo course whenever we install it

Improved argument parsing

Mark the start and end time of the installation

Improvements to install_stack.sh

Make ansible unbuffered for better experience while logging

(cherry picked from commit 8e995343)

Check for and uninstall pip packages

(cherry picked from commit f361f761)

(cherry picked from commit 276292aa)

(cherry picked from commit a8bd50f9)

Ecommerce and Programs need to play along with OPENEDX_RELEASE

Use logrotate to clean up from the log-queue-lenghts (sic) job

Passing the var

This reverts commit 694ed836.