(#1554) Add support for all common compressions (write and read)

- Remove the context.Context interface and export the *context, the iris.Context now points to the pointer\nSupport compression and rate limiting in the FileServer\nBit of code organisation


Former-commit-id: ad1c61bf968059510c6be9e7f2cceec7da70ba17

_examples/convert-handlers/nethttp/main.go

@@ -29,6 +29,3 @@ func main() {
 func nativeTestMiddleware(w http.ResponseWriter, r *http.Request) {
 	println("Request path: " + r.URL.Path)
 }
-
-// Look "routing/custom-context" if you want to convert a custom handler with a custom Context
-// to a context.Handler.