ability to specify a series of puppet modules

[anuaimi]

make it possible to include any public puppet module on github as part of this deployment. This is based on the model of ruby gems. Cloudbuilder will assemble all the module before launching puppet.

possible syntax:

puppet_module {module_name} {github repo name} 
puppet_module rvm git://github.com/blt04/puppet-rvm.git

since it is expected that most modules will come from github, the following shorthand should also be possible

puppet_module rvm blt04/puppet-rvm.git