[WIP] Use trollop option parsing for git reference instead of VERSION file

The VERSION file path as part of the nightly build scripts was not reliable.

Additionally, it feels ugly that the build code used to generate the kickstarts for the appliances needs to have access to the VERSION file from the desired branch/tag/reference.
@Fryguy I'm actually doing a hack.  You don't invoke the Cli directly.
You run ruby build.rb with the options and Build::Cli is used to parse ARGV.

But you're right, neither build.rb or cli.rb have shebangs as they were invoked with ruby.