Migrate unittest from master to ansi

* Add check as dependency
* Add test to cmake
* Make test_bitset ansi-c compliant and extend test
//TODO test_hashgrid and test_radixtree
Add tests coverage for missing bitset functions
Add documentation to bitset.h
enumerate and dump are DEBUG functions
Merge pull request #140 from skywave/ansi_tests

Migrate unittest from master to ansi