Refactored verbose logging, other minor changes
4oD: Refactored name resolution for proxied requests

Now disabled by default. Enable globally with boolean hidden preference
4oD_ResolveHostNamesForProxy
4oD: Refactored programme data retrieval, other minor changes
ITV: Refactored programme data retrieval, other minor changes
Refactored proxy loading, added optional proxy test

Proxy test on load is disabled by default.  It may be enabled with the
boolean hidden preference TestProxy.

The default proxy test URL is http://www.google.com.  An alternate
URL may be set with the string hidden preference ProxyTestURL.
Version 1.5.0+dp.12
Merge branch 'release/1.5.0+dp.12'