Added an exec resource to download Groovy.
Added an exec resource to unzip Groovy from the downloaded ZIP archive.
Added a before => parameter so we can ensure the download exec resource runs first.
Added an exec resource to move Groovy's extracted files out of the version numbered folder.
Added an exec resource to export the  environment variable.
Added an exec resource that exports a $PATH with the Groovy bin folder in it.
Escape dollar signs; we need literal dollar signs so that we actually echo in variables instead of an empty string, because Puppet interprets unescaped dollar signs as variables.
Comments are nice.