Add CClient::IsPlaybackActive()

To let modules know whether a client is currently in playback mode.
The clientbuffer module (#343) wants to update "last seen message"
timestamps in OnSendToClient() but it must avoid doing that while
in playback mode.

include/znc/Client.h

@@ -96,6 +96,7 @@ public:
 		m_bServerTime = false;
 		m_bBatch = false;
 		m_bSelfMessage = false;
+		m_bPlaybackActive = false;
 		EnableReadLine();
 		// RFC says a line can have 512 chars max, but we are
 		// a little more gentle ;)
@@ -128,6 +129,9 @@ public:
 	void BouncedOff();
 	bool IsAttached() const { return m_pUser != NULL; }
 
+	bool IsPlaybackActive() const { return m_bPlaybackActive; }
+	void SetPlaybackActive(bool bActive) { m_bPlaybackActive = bActive; }
+
 	void PutIRC(const CString& sLine);
 	void PutClient(const CString& sLine);
 	unsigned int PutStatus(const CTable& table);
@@ -175,6 +179,7 @@ protected:
 	bool                 m_bServerTime;
 	bool                 m_bBatch;
 	bool                 m_bSelfMessage;
+	bool                 m_bPlaybackActive;
 	CUser*               m_pUser;
 	CIRCNetwork*         m_pNetwork;
 	CString              m_sNick;