Report lessphp version number

I think it would be nice if the module can report the lessphp version number it's using. That will allow developers to look up which less functions can be used and check if the libraries module is loading the library correctly. The status report screen would be a good place, I guess.

Once you have the lessphp include path (just like _less_pre_render() does) you can use this code to get the version string:

  preg_match('#lessphp v[0-9\.]+#', file_get_contents($lessphp_include, NULL, NULL, 0, 200), $matches);
  $version_string = $matches[0];
  // $version_string is now "lessphp v0.3.1"

If you think this feature is worth implementing, I can try to create a real patch (or feel free to implement it yourself if you like :-)).