2014-08-31: Version 0.1.2
  * Change the field ref to matchIndex on the type=refernce node (issue #67)

2014-08-30: Version 0.1.1
  * Only handled unicode code point escapes if 'u' flag is set (issue #56)
  * Removed `matchIdx` from the AST
  * References like /\1/ were broken (issue #57)
  * Renamed type `ref` to `reference` in the AST
  * Update regex to match identifier and include script to generate regex

2014-06-29: Version 0.1.0
  * first tagged release