The 'path' is now simply Ruby's load path, prefixed with the global
'path' if it was set to a default value. Notably, this means the
current working directory is only included if Ruby itself included it
(true on 1.8, but not 1.9).
As discussed in gh-32:
1. It's slow.
2. It puts multiple versions of gems in the path, sometimes with older
gems coming before newer gems.
3. Does anyone actually want this?
As to #3, let's try dropping it and see if anyone even notices.