* librb is no longer a separately configured subproject.
* charybdis is now a standalone directory with a binary.
* Include path layout now requires a directory ircd/ rb/ etc.
This is similar to what exists in ircd, but instead of request ID's, we
return struct dns_query pointers (that are freed by the DNS callback, so
you don't have to worry about their lifecycle management).
This was an asston of pain, and it still feels "dirty" as it introduces
an async call where there normally wouldn't be one. Better
implementation more than welcome.
