Fast 2D matrix of bits

[bearophile]

Denis Shelomovskij:

> Is it? Every conditional branch can break CPU command queue and slow 
> down execution. Anyway, I saw same problem not far-away (2^n sized 
> OpenGL textures).

Hours ago Don has written a comment in one of my enhancement requests that is related to this topic:
http://d.puremagic.com/issues/show_bug.cgi?id=4046

I will do better benchmarks, and if necessary I'll update that helper function in the bit matrix code in Bugzilla (I have already fixed most of the other suggestions given by Timon Gehr).

If Don is right, this asks for some deprecation in core.bitops.

Bye,
bearophile