UnrealIRCd 6.0.4.1

This is a small update to 6.0.4. It fixes the following issues that were present in all 6.0.x versions:

• Fix sporadic crash when linking a server (after successful authentication). This feels like a compiler bug. It affected only some people with GCC and only in some situations. When compiled with clang there was no problem. Hopefully we can work around it this way.
• Make /INVITE bypass (nearly) all channel mode restrictions, as it used to be in UnrealIRCd 5.x. Both for invites by channel ops and for OperOverride. This also fixes a bug where an IRCOp with OperOverride could not bypass +l (limit) and other restrictions and would have to resort back to using MODE or SAMODE. Only +b and +i could be bypassed via INVITE OperOverride.