hashring.c: Fix #ifdef/#else comments to style(9)
Fix #6, as well as an issue introduced in ed9a7dcc

Issue from ed9a7dcc is that rehash() is totally broken for non-100
weights. Unit tests didn't catch that until I added some more for
(new) non-0 remove().

Notable changes:
- Store weights in hash ring itself. This allows us to rehash without
  keeping a seperate list of members and weights. Less juggling of
  memory, more expensive on the CPU. I think it is the right tradeoff
  for code complexity given my use doesn't add/remove often.
  * As a result, members are limited to 24 bits. Shouldn't impact my use
    noticably, however the unit tests assumed 32-bits in many places.
- We can no longer track hr_count (number of distinct members) cheaply.
  Dropped.
- hash_ring_getn() is a lot more expensive (O(n)) if you request an
  unsatisfiable number of members. I suggest you avoid making such a
  request.
- Add/remove gained an O(N+M) fixup pass; this should have minor impact,
  since they were and still are O(N*M) routines.

Update README to not mention 32-bit members.