Remove stale comment
Add a spec for Proc#== with rb_proc_new
Also consider @bound_method for equality
Add various specs for Proc#{inspect,source_location}
Remove extra spaces around @ for consistency
Correctly override #source_location at Proc::Method

Also, to make it happen, this versionizes Proc::Method#inspect.
Fix Proc#source_location because @block can be nil
Merge pull request #2156 from ryoqun/proc-fixes

Fix various proc bugs