Use mount point rather than directory for quota

Use mountpoint for quota rather than directory in filesystem.  "quota -f"
expects a mount point or device so grab that from "df".  Series of shell
commands taken from oo-init-quota.
Merge pull request #126 from kraman/bugfix

Misc Bugfixes
Merge pull request #121 from charlessimpson/node-quota

Use mount point rather than directory for quota
Generate quickstarts file based on selected cartridges