Update a bunch of `io` to `IO` in docs.
Make custom bitwise operators work, add tests
Merge pull request #26 from zeckalpha/feature/docs-io

Update a bunch of `io` to `IO` in docs.
Put custom bitwise operator tests into existing operators test file.
Merge pull request #27 from zeckalpha/feature/bitwise-operators

Make custom bitwise operators work, add tests