[LAZY] Updating Installer to point to FP 12 and AIR 4

[OmPrakash Muppirala]

If I remember correct, Erik's VM has had Mustella runs agains FP 12 and AIR
4 betas.  FP 12/4 was released yesterday.  I was planning on updating the
Installer to point to the new versions and make them the default.

Any objections?

Thanks,
Om