Make the library more (rebar) friendly

cherrypick and merge b1ad824ea39d43c690c68e685ddae816620c5b60
by Krzysztof Rutka <krzysztof.rutka@erlang-solutions.com>
syntax fix after merge
place tests compiled by make into 'tests' dir
move test/data back to test_data (to allow both rebar and make test find it)
Add support for uuid and uuid arrays (from soundrop: https://github.com/soundrop/epgsql/ )

Conflicts:
	src/pgsql_binary.erl
Added create_testdbs make target to create the test data.