Missing BackupMon project

[BrendanGrant]

In Chapter 12's sln file there is a reference to a BackupMon project, however that is not part of what is checked in.

It looks like it got added as part of this commit, though it's unclear to the reader if the reference was accidentally included or the code accidentally left out.

I'm still trying to wrap my head around so much in the book and the source, so do not know yet how important this is or not.

[zodiacon]

It seems it was accidentally left out of the repo. I have added it manually.
Thanks for noticing!