* ext/psych/lib/psych/scalar_scanner.rb: use constants rather than
  calculating Inf and NaN.
Fix case when map includes a symbol key in #emit_coder

Mimic what is done in #visit_Hash. Fixes #107.
sync with ruby trunk
* ext/psych/lib/psych/visitors/yaml_tree.rb: change output reference
  ids to be sequential numbers.
* ext/psych/lib/psych/visitors/yaml_tree.rb: fixing string quotation
  when dumping Ruby strings. Thanks Ingy

* test/psych/test_psych.rb: appropriate tests.

* test/psych/test_yaml.rb: ditto
* lib/psych/y.rb: Document Kernel#y [Github Fixes #127]
Missed author from 706545c
Do not use one-letter variables
* lib/psych.rb: rdoc for Psych overview by Adam Stankiewicz
  [Github Fixes #134]
* lib/psych.rb: specify in rdoc what object is returned in parser
  By Adam Stankiewicz [Github Fixes #133]
sync with ruby trunk
* ext/psych/lib/psych/visitors/to_ruby.rb: correctly register
  self-referential strings. Fixes tenderlove/psych #135

* test/psych/test_string.rb: appropriate test.
* ext/psych/lib/psych/exception.rb: there should be only one exception
  base class. Fixes tenderlove/psych #125
* ext/psych/lib/psych.rb: require the correct exception class
* ext/psych/lib/psych/syntax_error.rb: ditto
* ext/psych/lib/psych/visitors/to_ruby.rb: ditto

fixes #125
change test name to be more helpful. fixes #124
Merge pull request #122 from tjwallace/fix_coder_emit_hash

Fix case when map includes a symbol key in #emit_coder
Remove remaining .swp file
Update rbx install docs
Merge pull request #131 from sheerun/fix/naming

Do not use one-letter variables
Merge pull request #141 from kdisneur/fix/remove_swp_files

Remove remaining .swp file
merging from Ruby