Test enum
Test enum on table
Merge branch 'master' into issue/16

* master:
  Migrate from HTF to Hspec
  Reorganize tests, use "doctest"
  Restrict the "either" dependency
  Extend the "list-t" dependency

Conflicts:
	tests/Main.hs
Merge branch 'master' into issue/16

* master:
  Exclude the building of benchmarks with lower-bound dependencies
  Correct the use of "shouldBe" of Hspec
  Update the phrasing of specs
  Let the unit result handler not fail on statements, which do produce results
  Clean up after the removal of the library tests
  Build benchmarks optionally
Correct the specs
Added Mapping instance for PGEnum
Merge remote-tracking branch 'origin/issue/16'
Import test cases for PGEnum and added the explicit Mapping instance
for PGEnum.
Modified enum tests with the new PGEnum type