CDRIVER-403 Allow count to work with query hints

Support an optional bson_t opt param for count which masses args through
to the count command unchanged.  This allows the user to pass arbitrary
hints.

Adds a new function to the abi
CDRIVER-450 Update expected ABI
Merge pull request #106 from spencerjackson/CDRIVER-450

CDRIVER-450 Update expected ABI
CDRIVER-442 reimplement mongoc_database_has_collection using mongoc_database_get_collection_info
CDRIVER-415 Add documentation to deprecate dropDups

Closes #105