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
CDRIVER-404 Implement SCRAM-SHA-1 SASL Mechanism

Implements Scram Sha1 for the c driver
CDRIVER-429 Bump maxWireProtocolVersion

Closes #107
CDRIVER-427 move header include guard above checks
don't use sasl_client_done on OSX Yosemite

it looks like the provided libsasl2 on Yosemite isn't quite right (it
reports a sasl_version of 2.1.26, but doesn't provide all the symbols
that version should provide out of the actual dylib).  Conditionally
skipping calling that function for now on OS X.
Merge branch 'mongodb-master'