Add a column to mongostat that provides a count of all aggregate-like commands

It's most likely confusing for users that only a non-command OP_QUERY and the find command are counted as a query in mongostat, but other query-like commands are not.

To that end, it would be useful to have a column in mongostat that includes all the other query-like commands, which include all the commands that do aggregate-like operations:

• aggregate
• mapReduce
• count
• distinct
• group