Support ipv4 inet values on Windows

See https://issues.apache.org/jira/browse/CASSANDRA-4801
Fix test_prepared_queries.py
Fix native proto prepare implementation

queryid is an uuid now, not an int
Make test_index_scan_equality order-agnostic
Fix packing of 0 as a varint value

Fixes #42. This was causing serialization of varint(0) and Decimal(0) to
fail.

Add tests for serializing 0 in varint contexts.