MB-10957: Add python snappy module

Change-Id: Ia59c808872aa391b38eb36a273faa2a0ad813a54
Reviewed-on: http://review.couchbase.org/36906
Reviewed-by: Philip Labee <philip@couchbase.com>
Reviewed-by: Steve Yen <steve.yen@gmail.com>
Tested-by: Bin Cui <bin.cui@gmail.com>