PostgreSQL 10 reports its version as only `major.minor`, so it can’t be parsed with semver. The `server_version_num` setting is a major version followed by a four-digit minor version since version 10, and was a three-digit major version followed by a two-digit minor version before that.
* Initial work on removing internal pool
* Port backwards-compabible properties
* Cleanup test execution & makefile cruft
* Attempt to fix flakey error test
1. Pass an error to an active query if the client is ended while a query is in progress.
2. actually emit 'end' event on the client when the stream ends
3. do not emit an error from native bindings if lasterror is null
