Feature request: Make ProxySearch a bit more extendable

[heatzync]

The ProxySearch class only accepts predefined instances of ProxySearchStrategy due to the use of the Strategy enum.

Feature request:

• Add a ProxySearch#addStrategy(ProxySearchStrategy custom) method.

This will allow one to add custom ProxySearchStrategies to the list of possible strategies. I would like to do:

ProxySearch proxySearch = new ProxySearch();

proxySearch.addStrategy(new SomeCustomProxySearchStrategy());

[gschnepp]

This project is dead. Just use another fork like https://github.com/akuhtz/proxy-vole