Extend response override plugin capabilities

Give plugins access to response, original request information
Plugin extension update

Keep old plugin compat
Response override can block request
Rename v2 ResponseOverride
merge master
Clean status plugin
Add response content helper
Exclude new properties from backup
Refactor common code in callFunction methods
add missing args
Remove extra semicolon
Merge pull request #32 from groupon/dwillson/12

Extend plugin support