Merge branch 'release/0.12.0' into develop

* release/0.12.0:
  Bump soversion for 0.12.0
128-bit integers on GCC 4.1-4.5

So it looks like the `__int128` type isn't actually available until GCC
4.6.  From 4.1 through 4.5, it looks like we can mimic this type using
the `mode(TI)` attribute.
Bump soversion for 0.12.1
Merge branch 'release/0.12.1'

* release/0.12.1:
  Bump soversion for 0.12.1
  128-bit integers on GCC 4.1-4.5