added the env so it can be accessed from the routed endpoint block

Right now the routed endpoint provides access to the app and to the params. 

However, in many cases you may wish to have access to the full ENV so that you can look at the full HTTP headers. I specifically want this to look for API tokens I place in the header (as I want to keep them out of the url) but I can imagine other uses for this including special handling for if-modified-since, etags, etc.

In an ideal world I am not sure I'd make it the last variable provided to the block, but placing it there now should prevent this change from impacting existing apps.