Restructured node mapping so common cases are evaluated first, saving unnecessary comparisons.
embedding libyaml
for compiling on mswin

I checked only mswin environment.
Maybe it is required for mingw?
Merge pull request #101 from tarui/embed

for compiling on mswin
only embed libyaml if the system does not have it
fix build on windows
mkmf has a global for this test
only do have_header checks if we are embedding libyaml
fix c file name
Merge branch 'master' into embed

* master:
  * ext/psych/lib/psych/scalar_scanner.rb: avoid raising exceptions when   parsing Floats and Integers. Thanks riffraff [ruby-core:44426] * test/psych/test_numeric.rb: associated test
  * ext/psych/lib/psych/core_ext.rb: move Kernel#y so that it can   manually be required as 'psych/y'.
  Use literal style when emitting multiline strings, fixes #64
Merge branch 'master' into embed

* master:
  Update README.rdoc
  * lib/psych/deprecated.rb (load_documents): document deprecation
add the license for libyaml
updating the version to 2.0
make some header file adjustments for ruby compile
fixing rsync
Strings that start with non-word characters should double quote without exclamation mark

Before this commit:

--- ! '@123''abc'

After this commit:

--- "@123'abc"
Merge pull request #106 from atambo/master

Strings that start with non-word characters should double quote without exclamation mark
Merge branch 'embed'

* embed:
  fixing rsync
  make some header file adjustments for ruby compile
  updating the version to 2.0
  add the license for libyaml
  fix c file name
  only do have_header checks if we are embedding libyaml
  mkmf has a global for this test
  fix build on windows
  only embed libyaml if the system does not have it
  for compiling on mswin
  embedding libyaml
merge changes from ruby trunk
Merge branch 'master' into nirvdrum-speed_up_node_mapping

* master: (28 commits)
  merge changes from ruby trunk
  Strings that start with non-word characters should double quote without exclamation mark
  fixing rsync
  make some header file adjustments for ruby compile
  updating the version to 2.0
  add the license for libyaml
  Update README.rdoc
  fix c file name
  only do have_header checks if we are embedding libyaml
  mkmf has a global for this test
  fix build on windows
  only embed libyaml if the system does not have it
  * ext/psych/lib/psych/scalar_scanner.rb: avoid raising exceptions when   parsing Floats and Integers. Thanks riffraff [ruby-core:44426] * test/psych/test_numeric.rb: associated test
  * ext/psych/lib/psych/core_ext.rb: move Kernel#y so that it can   manually be required as 'psych/y'.
  for compiling on mswin
  embedding libyaml
  * ruby.c (load_file_internal): set default source encoding as   UTF-8 instead of US-ASCII. [ruby-core:46021] [Feature #6679]
  * ext/psych/lib/psych/handlers/recorder.rb: added a class for   recording YAML parse and emit events.
  Use literal style when emitting multiline strings, fixes #64
  * ext/psych/lib/psych/visitors/yaml_tree.rb: `tree` should return the   same thing on every call.
  ...