Remove rvmrc
Add ruby-gemset
Remove unnecessary installation section from README
Change README to use different markdown style
Move contribution guidelines into separate file
Change gemspec to only depend on bundler for development deps
Change rspec to use expect syntax

* Add support files for rspec
Refactor descendants method to be an attr_reader
Refactor ivar name to be a Symbol
Remove setup method and alias to extended
Add YARD docs for extended
Change flay threshold
Change reek configuration to use new format