Update psych to edf05c9f40e0c566e391f7e04b4a30327c31a828

There's tons of string quotation fixes that I would :heart: to see in jruby 1.7.4. In order to generate this diff I ran the following commands:

```cp -R <psych checkout>/psych/lib/psych <jruby checkout>/lib/ruby/1.9```
```cp <psych checkout>/psych/lib/psych.rb <jruby checkout>/lib/ruby/1.9/psych.rb```