This adds a series of archetypal containers that represent the
common use cases (arrays, bitmaps, or runs of various cardinalities)
and runs the basic operations against them for benchmarking purposes.
`benchpretty` is an app to snatch the BenchmarkCt* lines from
benchmark runs and display them in a possibly more usable form,
mostly as a precursor to cool analysis things.
This also adds a test to verify that intersectionCount(a, b)
is the same as intersect(a, b).N() for all the archetypal
containers.
This also includes a performance fix for intersectBitmapRun which
was spotted while running these tests.
