no duplicated yaml in jar files

jruby-core.jar or lib/jruby.jar has yaml/** ruby scripts almost the same as jruby-stdlib.jar

there are differences ! and it is just a bad to have different version of the same files
in the system (load-path or classpath etc)

I consider this a bug since once you ```classpath:``` or ```uri:classloader:``` to $LOAD_PATH you might switch to another version of yaml :(
this actually happens when you use IsolatedScriptingContainer !

@enebo @ratnikov