Update web.go
Merge pull request #61 from RuiAAPeres/patch-1

Update web.go
Document package web/util
Support Tee() in the ReadFrom case as well
Major API change to use context.Context instead of *web.C

The options middleware is currently broken (must be rewritten another way) but it looks like everything else should work fine
Make sure to only allocate a context with valid methods if necessary
Use net/http.Server.SetKeepAlivesEnabled in Go 1.3

This feature can be used in place of the pile of hacks in middleware.go,
and doesn't involve awkwardly shimming out a http.ResponseWriter. Sounds
like a win-win!
Rewrite AutomaticOptions as a NotFound handler. The rewritten tests now pass.
Port example to new context API
Merge remote-tracking branch 'origin/master' into context

Conflicts:
	example/main.go
Slight simplification of netHTTPWrap
Minor context optimisations/cleanups :
- use a global background context since it is immutable
- no need to set the context in *mStack.newStack() and *cStack.ServeHTTPC()
(cStack.ctx is set only when necessary by the translation layer fromHTTPHandler)
Uncomment and fixup TestValidMethods
Since we have immutable contexts, simplify the Pattern interface.

As a related change, url parameters are now created in a new context regardless of the fact that the enclosing environnement may already contain url parameters.
We now ensure that the enclosing context is not modified.