Add some more tests
Move Class module to the tests
Make some PSQ functions conform to the interface
Fix the benchmarks
Add props for toList/fromList and fold'
Add Makefile for running hpc
Implement fold in Data/PSQ.hs
Cover some cases
Implement fold in Data/PSQ.hs: remove unnecessary code
100% coverage for IntPSQ yay
Merge branch 'master' into psq_delete_view

Conflicts:
	Data/PSQ.hs