Use OnChanRegistered instead of OnCreateChan to set default mlocks.

Because OnCreateChan is called from ChannelInfo's constructor, during
DB loading it could cause mode locks to be unserialized without having
all channels loaded, which breaks things.
Remove unused event.
Mark some oper only usermodes as oper only.
Fix reading SID in TS6_SID_Retrieve
Fix SVSNICK target being a nick even when UIDs are available
Merge pull request #72 from attilamolnar/2.0+svsnickfix

Fix SVSNICK target being a nick even when UIDs are available