Full regex support

[ritenv]

Support for full RegEx patterns would be extremely helpful, and expected (works for the grunt counterpart)

<!-- include:js(system/**/!(*.module).js) -->

[ritenv]

Below is what works:

function matchExpressions(contents) {
  return contents.match(/<!--\s+include:([a-z]+)\(([^\s]+)\)\s+-->/);
}

Basically, I replaced ^) with ^\s to rely on the last space character. Not the prettiest solution, probably.