From a functional point of view, the main improvement is that GetIP() now always prioritizes IPv6 over IPv4.
The previous implementation always returned an IPv4 address, unless not available: in such case it failed.
This means that now connections to hostnames should be established via IPv6 if available.
From a programmer point of view, getting rid of the insane wrappers is enough to justify a complete rewrite.
As an extra, several unrelated unused global variables are removed.
This commit moves the generic (not related to our protocol) proxy stuff from Cedar to Mayaqua, in dedicated files.
The functions are refactored so that they all have the same arguments and follow the same logic.
Dedicated error codes are added, in order to indicate clearly why the function(s) failed.
