Add OnSendToIRCMessage and OnSendToClientMessage

This also alters PutClient such that the CMessage variant handles
sending messages, rather than the CString variant. As a side bonus, this
gives callers better information on whether the message was sent to the
client. Additionally, it eliminates the need for a hook to let modules
set the tags sent to a client, as that can now be done inside
OnSendToClientMessage.

modules/modpython/module.h

@@ -173,6 +173,8 @@ class ZNC_EXPORT_LIB_EXPORT CPyModule : public CModule {
     EModRet OnPrivNoticeMessage(CNoticeMessage& Message) override;
     EModRet OnChanNoticeMessage(CNoticeMessage& Message) override;
     EModRet OnTopicMessage(CTopicMessage& Message) override;
+    EModRet OnSendToClientMessage(CMessage& Message) override;
+    EModRet OnSendToIRCMessage(CMessage& Message) override;
 
     // Global Modules
     EModRet OnAddUser(CUser& User, CString& sErrorRet) override;