The actual change is in src/mongo/shell/collection.js with the remaining changes
to adjust tests to the new api.
The "ideal" arguments are now an array of pipeline ops and an optional object
with extra top-level options for the command (such as {explain: true}. For
backwards compatibility, we still support the varargs style where each argument
is a pipeline stage, but there is no way to specify extra parameters in this
mode.
Related tickets:
SERVER-6571 replace use of Undefined as missing with EOO
SERVER-6471 ignore nullish values in $min and $max accumulators
SERVER-6144 divide by zero makes field disappear (this solution isn't final)
