Remove support for configuring http proxy
The Vidalia proxy settings page lets you choose socks4 or socks5 or http or http/https. Choosing http just means that your plaintext directory fetches are proxied -- and most clients don't do plaintext directory fetches anymore.
Users are being confused into choosing 'http proxy' when they ought to choose 'http/https proxy'.
We should just remove the ability to pick an http proxy. Bonus if it means some code simplification on the backend (I think it's fine if Vidalia loses the ability to configure the HttpProxy torrc option).