Add spec for concurrent autoloads
Fix race condition in autoload specs
Add spec to check for super caching
Spec for Regexp#encoding from ascii chars with non-ascii encoding.
Specs for rb_usascii_encoding and friends.
Fixed some compile warnings in C-API specs.
Specs for rb_enc_find_index, rb_enc_from_index.

These specs royally suck but the only other option is to leave them out
entirely since they are really testing implementation details that MRI
should *never* expose but does and people are using these functions in
things like database adapters.
Specs for rb_enc_from_encoding.
Specs for rb_to_encoding.
Spec for rb_eEncCompatError.
Move RangeError spec to own group

NAN & non-positive precision raises a RangeErrorm not a
FloatDomainError.
Fixed some Encoding.default_internal specs.
Specs for Encoding.default_external with cmd line options.
Updated File.identical? spec
Updated IO.copy_stream spec
Cleanup the Proc#== specs on 1.9
Changed Enumerable#inject, Enumerator#each_with_index and Enumerator#with_index to use Rubinius.single_block_arg, which should fix #1457
Adding spec that caught a bug in rbx's impl of Float#round
Fix typo
Specs for rb_enc_copy.