Update cookbook and add auto/non-auto and --install-dir functionality

* Update bundled gems
* ignore .bundle/ to allow less intrusive testing
* allow user to set `ruby-install` destination dir (`--install-dir`)
* allow user to use `chruby` in auto or non-auto mode
* `chruby` recipe is responsible for calling `default_ruby` recipe
* `defautl_ruby` handles auto and non-auto behavior of chruby