Issue #118: Bundle a script for installing Backdrop from the command line.
Merge pull request #91 from quicksketch/118/install-script

Issue #118: Bundle a script for installing Backdrop from the command line.
Issue #11: Move modules and themes out of sites directory
Issue #11: Move modules and themes out of sites directory - update 2
Issue #11: Remove sites/all directory and move modules and themes to the root.