Better test of monochromatic make_scheme

I realized the test wasn't complete. Only {scheme_type: "mono"} was
being tested, but {scheme_type: "monochromatic"} should be tested too.
Therefore this test was been refactored to test both without needlessly
duplicating code.
Test for complementary color schemes

This commit adds tests for complementary color schemes. Both
{scheme_type: "complement"} and {scheme_type: "complementary"} are
tested.

Other make_scheme tests are now xdescribe'd.
Split-complementary test

Test fails, some failures may disappear after merging from upstream.