Test index addition of the `query` features.

[ci skip]
Improve the `query` feature's test coverage.

Tests are currently failing.
[ci skip]
Bootstrap the query module.

[ci skip]
Add more utility functions.

These implementations are really small, necessary, and faster than the
native or lodash implementations, so I don't think the trade-off is that
bad, even though I'm polluting this module with methods which are outside
of its scope.
Fix bugs in the `query` module. Tests now pass.