fast_memoize

https://github.com/dfurber/fast_memoize

If you are used to doing memoization with `@my_method ||= yada_yada` and `return @my_method if defined?(@my_method); @my_method = yada_yada`, but you would like to get the memoization stuff out of the `yada_yada` part, but still rest assured that the `memoize` method does nothing more than that, then this gem is for you.