Backed out changeset b6c206049d8a
The nvmemmory library depends on a modification to qemu; this change
is therefore backed out in order to allow NVM functionality to be
merged into graphics-phase-3 by transplanting individual commits.
The icons for use on MacOS X were created by Jacob Rus <jrus@fas.harvard.edu>with some feedback from the folks on pythonmac-sig@python.org.