Change file names to not include version numbers in features

If the name of a file such as a JS or CSS in a feature contains a version number, e..g jquery-1.6.4.js, this makes it much more difficult to update the feature to use a new version, as existing widgets will continue to point to the file name originally injected, which may no longer be installed on the server.

To avoid this we should make sure resources used in features use generic filenames, or stick to major version names (e.g. "1.0","2.0") and not minor or beta version identifiers.