Updates for cli and context

cli adds new global options. We'll be able to specify flags that
apply to multiple options now.

context update fixes parallelWriter function, actually writes a value out now.

Godeps/_workspace/src/github.com/gorilla/context/context_test.go

@@ -98,7 +98,7 @@ func parallelReader(r *http.Request, key string, iterations int, wait, done chan
 func parallelWriter(r *http.Request, key, value string, iterations int, wait, done chan struct{}) {
 	<-wait
 	for i := 0; i < iterations; i++ {
-		Get(r, key)
+		Set(r, key, value)
 	}
 	done <- struct{}{}