LVM adjustments for 3.7.x and vagrant local caching

This supersedes PR 410 - I merged it upstream for testing the LVM changes.  So this PR adds the local caching for vagrant builds.

- Adds the vcsrepo module to the boostrap so that we can use it for managing the courseware-lvm content instead of using wget.
- Adds some JVM memory defaults that may allow VMs as low as 2gb (or 1gb + 1gb swap).  Further improvements and testing to come.