Fixed String subclassing

Atring.allocate should not ignore sublasses and should
pass `self` as `klass` to `W_Object.__init__`

Untagged specs:
 * fails:String.new returns an instance of a subclass
 * fails:String.new is called on subclasses
Removed 'fails' tag from passing spec

This was fixed in ad97fbbe652f0bdff70069fe43ed7b0f65b1fee8
Failing example used subclass of String while such subclassing
was broken.
simplifiy and fix jittests
Merge pull request #1 from topazproject/tim/string_new

simplifiy and fix jittests
A bunch more passing tests.
more passing specs
Reverted JIT fixes to master version
more specs which pass
Merge pull request #536 from krekoten/string_new

Fixed String subclassing
more passing specs
more correct errors
Moving the RUBY_REVISION part of version string to be more MRI-ish

per conversation on #514
Merge pull request #537 from modcloth/mbh/ruby-revision-shuffle

Moving the RUBY_REVISION part of version string to be more MRI-ish
make these spec tags more accurate
Merge branch 'master' of github.com:topazproject/topaz
things which pass
unskip some env tests
unskip float specs
iunskip io specs
unskip some kernel specs