Log Message:
Update to 1.43

Upstream changes:
1.43 Fri Oct 23 14:00 2015
  - Update copyright + version correctly everywhere

1.42 Fri Oct 23 13:30 2015
  - Allow get_and_set callback to return an empty list
     which means "no change". This allows atomic
     "get, and set if not present" type action, but
     without resetting the expiry time on each get.
     This is basically the same as using the read_cb

1.41 Thu Aug 29 15:30 2013
  - Actually reuse deleted slots. Meant that if
     you used ->remove() a lot, we would re-organise
     cache more than needed
  - Include typo and meta patches from dsteinbrunner