Allow configuring many proxylists.

Now 64 separate chains are supported (easy to change).  A chain is selected using the PROXYCHAINS_CHAIN envvar.  I leave the default list as "ProxyList" for backwards compatibility, but I think it should really be default.  Chain names can be any string excluding the ']' character.  There are per chain timeout, chain type, and man_chain settings.  If these are no specified the global values will be used.  In case its not obvious, this is build on the round robin patches, in the other pull request.

This is a step on the way to allowing chaining of proxy chains, the original goal.  The next step though will be tricky and I'm not even sure I have the semantics fully thought out.