Log Message:
Import ruby-mini_portile2-2.1.0 as misc/ruby-portile2.

Note ruby-mini_portile2 is updated and renamed version of
ruby-mini_portile by the upstream due to backwards-incompatible
behavioral changes from mini_portile 0.7.0.rc* and prior.

This project is a minimalistic implementation of a port/recipe system
for developers.
Because "Works on my machine" is unacceptable for a library maintainer.