frama-c: overhaul, upgrade to 20140301-Neon

This massively upgrades the frama-c package to be far more useful,
including support for a lot more plugins, including Jessie.

Jessie unfortunately requires that its plugin is installed alongside
frama-c, so we install why2 (where it lives) along with frama-c now.
This increases the size, but makes it much more useful.

In the future, it may be possible to split out the build such that why2
is a separate expression and frama-c only installs the plugin, rather
than all of why2. However, right now this is fine.

Furthermore, why3 is now a dependency - the Jessie plugin can use
either, and defaults to Why3 now. Per the design, Frama-C can also go
from Why2->Why3 as well.

We also make Coq and Alt-Ergo dependencies, so that out-of-the-box users
get at least one SMT solver and a prover for support.

Signed-off-by: Austin Seipp <aseipp@pobox.com>