More abstractions for low-level code patterns

[sjakobi]

The main advantage of having proper functions for these code patterns is that the functions can have proper documentation.

• incrementShift s = s + bitsPerSubkey (Done in Introduce nextShift #432)
• anyMatch b1 b2 = b1 .&. b2 /= 0
• isolateLowestSetBit x = x .&. negate x (Alternative to countTrailingZeros for bitmap iteration #424)

[sjakobi]

I'm becoming less convinced that introducing anyMatch b1 b2 = b1 .&. b2 /= 0 would be a good idea. It would probably involve re-ordering branches, e.g. where currently b .&. m == 0 comes first.

I also suspect that the pattern is sufficiently simple that additional documentation isn't too important.

[sjakobi]

clearLowestSetBit x = x .&. (x - 1) might be a useful addition.