Protobuf serialization format as default.
Make semantics of ImplyFactorFunction consistent with DeepDive. Fix Parsing for TSV format.
Use unsigned integer in protobuf.
Fix tests to work with new ImplyFactorFunction semantics.
Fix tests to work with new ImplyFactorFunction semantics.
Make semantics of ImplyFactorFunction consistent with DeepDive. Fix Parsing for TSV format.
Merge branch 'protobuf' into develop
Use streaming for protocol buffers.