make http proxy port configurable in cxml, avoiding this: org.springframework.beans.NotWritablePropertyException: Invalid property 'httpProxyPort' of bean class [org.archive.modules.fetcher.FetchHTTP]: Bean property 'httpProxyPort' is not writable or has an invalid setter method. Did you mean 'httpProxyHost'?
Merge pull request #31 from nlevitt/proxy-port-configurable

make http proxy port configurable in cxml, avoiding this: org.springfram...