statically allocated bitmaps

[bgoglin]

@elfarouk wants statically-allocated bitmaps to avoid memory fragmentation. Not easy with the current implementation. If we implement bitmaps that are already preallocated #255 and we say that applications using higher bits are buggy, we could extend to statically allocated bitmaps.

[sthibaul]

AIUI it's just a performance question. We could let the application just configure the default bitmap size, and use that as default allocation for bitmaps. If the application doesn't go beyond it, there won't be reallocations, if it does, there will be reallocations, but that will only have performance consequences.

[bgoglin]

Moving this to Future instead of v2.1 since @elfarouk didn't provide a test case for looking at fragmentation issues.