Merge branch 'release/2.3.0' into develop
[CS] CI build on ruby 2.0.0
[CS] Switch from Flexmock to rspec-mocks

* All other ahn projects have switched.
* It's one less dependency.
* Flexmock doesn't play nice with BasicObject, for example Celluloid proxies
[BUGFIX] Fix another Celluloid deprecation warning
[CS] Whitespace
[DOC] Add FreeSWITCH to another place in the README
[DOC] It's 2013
[DOC] Changelog entry
[UPDATE] Bump to 2.3.1
Merge branch 'release/2.3.1'