Brings module up-to-date with the latest version of drush.
* Issue #2278999 by jh3: Warnings on every drush command "array_key_exists() expects parameter 2 to be array, null given engines.inc:259 "
* Issue #2597331 by jh3: Call to undefined function drush_core_find_project_path()
Small change to have '=' in the command line options, it doesn't seem to need them but I prefer them to match *all* other command line parameters I use...