[ANN] flay 2.9.0 Released

flay version 2.9.0 has been released!

* home: <http://ruby.sadi.st/>
* code: <https://github.com/seattlerb/flay>
* rdoc: <http://docs.seattlerb.org/flay/>

Flay analyzes code for structural similarities. Differences in literal
values, variable, class, method names, whitespace, programming style,
braces vs do/end, etc are all ignored. Making this totally rad.

Changes:

### 2.9.0 / 2017-04-13

* 1 minor enhancement:

  * Added Sexp#pure_ruby_hash from flay-persistent and switched structural_hash to it. Faster than ruby's #hash and stable.