Is the current OpenStudio installation version 1.6.0 or development versions 1.6.x only compatible with Ruby v2.0.0-p594 as implied in the release narrative or can later builds such as v2.0.0-p598 or later versions such as v2.1.5 be used as the Ruby compiler for measures? Does the Ruby version (x64) need to be the same as the OpenStudio version