Use multiple instances of ITLogBook to work with different logchannels

When an instance ITLogBook opens a logfile it makes the logchannel directory of this logfile the current logchannel directory of the ITLogBook instance. When you invoke Open Recent Log later it will open the latest logfile of this logchannel.

Different instances of ITLogBook can use different logchannels as their current logchannels, so take advantage of this.

To quickly start an instance of ITLogBook that uses a predefined logchannel, use the Windows explorer shortcut trick.