Add user entered ID validation
Add user entered ID validation

Pengo now checks the user entered number against the actual number of
documents in the database.  The error message includes a hard-coded
maximum value (77), which should be dynamically gotten from the database
count function.

peterjmartinson/PengoBot,mtanzillo/PengoBot,mtanzillo/PengoBot,peterjmartinson/PengoBot