Testing custom character-based class.
Testing 8bit ascii_only strings.
Changed Psych::Visitors::YAMLTree.binary?(string).

* A human-readable representation can be used for ascii_only 8bit-encoded strings.
* String subclasses are binary, even if they are character-encoded.
Merge pull request #113 from pck/improve-string-encoding

Improve string encoding
* ext/psych/lib/psych/scalar_scanner.rb: strip trailing dots from
  floats so that Float() will not raise an exception.

* test/psych/test_numeric.rb: test to ensure "1." can be loaded

* test/psych/test_string.rb: make sure "1." can round trip

fixes #109
* ext/psych/lib/psych/visitors/to_ruby.rb: merge key values that
  contain something besides a hash should be left in tact.

* test/psych/test_merge_keys.rb: test for change

fixes #114
* ext/psych/yaml/scanner.c: Typos by James Dabbs [Github Fixes #118]