New version param for package ensure

Allow a specific version to be passed into the Package[] resource. This
could also be used to remove the package. However it will continue to have
no effect on OSX platforms.

The value `installed` is now quoted, in reality this makes little
difference.
Merge pull request #3 from dcarley/version_param

New version param for package ensure
Release 1.0.0
Add verbose option to enable toggling of wget output but set by default to non verbose
Release 1.1.0