More-better-er overrides, fixed smartgroup logic

With the new *LEAVE_OUT* keyword that can be assigned in an override,
you can now choose to remove an optional input without modifying the
parent jss recipe. Also the smartgroup logic was looking for
Application Title %Name% instead of %Name%.app, fixed.
Added info from blog post to readme, including current known issues
that are jss-specific.
Update version.plist
Added a test for whether a package is flat or not; used to determine shutil method for copying.
Merge pull request #8 from sheagcraig/copyfile_copytree

Added a test for whether a package is flat or not
Added policy categories. Changed policy names to be fully specified in input variables.