Speed up bitmapSearch

[DictumMortuum]

Do didn't ask about performance, but you can speed up bitmapSearch for sparse bitmaps by first looking at a byte at a time. If looking for a 1, you can skip bytes that are 0x00, and if looking for a 0, you can skip bytes that are 0xFF. After that, you can scan the bits on the next byte or use a look-up table on it.

I'd also have bitmapSearch take its size as a bit count instead of a byte count. Then if the client only cares about, say, 26 bits for letters, they don't have to worry about a search returning 27 because the bitmap really have 32 bits in it.