Update request module and node engine requirements
Remove path.existsSync as part of node 0.8 minimum environment
Update IO history
Update core history
Merge branch 'request-update' of git://github.com/clarle/yui3 into dev-master
Merge branch 'dev-master' into dev-3.x

Conflicts:
	src/io/HISTORY.md
	src/yui/HISTORY.md