Add new utility function, for debug and testing. Remove #import from pch; include per file as needed.
Move "count" property up into BABitArray protocol. Implement in conforming class.
Fix memory leak.
Add new utility method for finding leaf node from leaf index.
More testing and fixes.

Fix calculation bugs in copyBits() function. Add custom implementation of -subArrayWithRect: in sparse bit array to not use -[BABitArray initWithArray:rect:], which uses -readBits:range:, which does not handle index ordering differences for multi-dimensional sparse arrays. Add a new method to read a range of bits starting from 2D spatial coordinates. Revise read/write methods to return count information.