Enable specs to run against ruby or io-like

rake test to test io-like
rake test_ruby to test native ruby - these currently fail
against 1.9 because some of our tests are not 1.9 aware
MRI 1.9 passes our specs

exposed some 1.9 behaviour that our tests covered and rubyspec didn't
still to fix rubyspec for ungetc
Update and pass latest rubyspecs

resolves many "needs to be reviewed for spec completeness"
many additional specs related to encodings
one addition test for 1.8.6 is skipped rather than fixed for io-like