Add support for converting blocks into function arguments in JavaScriptGenerator#call and JavaScriptProxy#call.  
Add JavaScriptGenerator#literal for wrapping a string in an object whose #to_json is the string itself.


git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@5323 5ecf4fe2-1ee6-0310-87b1-e25e094e27de