Remove ‘-wKU’ from the shebang inserted with ‘rb⇥’

This improves portability as some platforms do not support multiple interpreter arguments, plus ruby 2.0 states that using -K “may cause odd behavior”.

If you do want the options then set TM_RUBY_SWITCHES in Preferences → Variables or .tm_properties (to the options you want).
Use /usr/bin/env ruby for commands.
Merge remote-tracking branch 'upstream/master'