[PATCH v2 0/2] fix for #285

[Emilio Cota]

Changes since v1:

- Add configure check to only use QTree if Glib still implements gslice.
  If Glib doesn't, then we call Glib directly with inline functions.
- Add TODO's so that in the future (i.e. when the minimum version of
  Glib that we use doesn't implement gslice) we remove QTree.
- Add comment to the top of qtree.h.
- Make qtree-bench results more robust by running longer or more times.
- Drop deprecated API calls (they're unused in QEMU).
- Drop API calls that are too recent (they're unused in QEMU).
- Drop macro benchmark results from the TCG patch since they're too noisy.
- Add test program to the commit log so that we don't lose it in the future
  even if the bug tracker goes away.

Thanks,
                Emilio