Revisions and Versions

 Is it possible to limit the amount of revisions of a document kept in the file manager?  Is it also possible to keep the number of versions of a document to a limit.  For example we have a document that we have put a change order against many times.  We only want to keep the last three revisions of that document in Agile.  How do we purge the other revisions?

Similarly, within a document revision users are checking the document in and out and that is creating different versions of the document  Is there a way to put a limit on how many we have of those?