Moved maxMemoryForMultipartForm and SetMaxMemory as members of FormValueProvider

Seemed to make more sense with the ParameterValueProvider stuff going on
Update README.md

Just added a link to godoc.org so people can easily view the source documentation
Added a couple of basic ActionWrappers.

PostOnly prevents any type of Request making it to the handler except
those made with the POST method.

OnPost calls a differnt handler in case of POST requests, allowing you to
keep form handling in it's own seperate handler if you wish.
go fmt on package
Update action.go

Fix error with documentation around action wrappers.