MTCountAssignments: Function to increment a counter of assignments
In andrewbrownphd/MetaTurkR: Functions to Support Metaresearch with MTurkR

This function fetches the count of assignments a worker has completed from MTurk, adds a counter for newly completed assignments, and posts the new count.

1 2	MTCountAssignments(results = NULL, counterQual = NULL, approve = FALSE, sandbox = TRUE)

`results`	A results object returned from MTurk.
`counterQual`	The qualification ID string that identifies the counter qualification for this HIT.
`approve`	Logical. Whether to approve assignments after counting. This will return the `results` object, but with `AssignmentStatus` set to `ApprovedLocal`. Default is `FALSE`.
`sandbox`	Logical. Whether to use the sandbox (`TRUE`) or not; default is `TRUE`.