We settled on a powerful, but a bit complicated acl design.
This commit makes a couple of cosmetic improvements. It also removes
http.Transport, which was previously used to dial and write http
requests for insecure GET requests. Now we have to dial manually,
so we can check the access control list.
Fixes: abnormal ContentLength; empty schema due to the out of position check.
Handling of HTTP GET requests: original request and URL are now reused. `generateForwardRequest()` is removed for simplicity.
