chromium: Don't use v8 from <nixpkgs> anymore.

The version of v8 to use for Chromium is heavily tied to the specific
version of Chromium and thus it doesn't really make sense to use v8 from
<nixpkgs>, as we would need to have 3 different versions of v8, one for
each Chromium channel.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
chromium: Update all channels to latest versions.

XXX -              HYDRA PICKUP              - XXX

  ++   +    + ++++++ +    + +++++    +    + ++++++
 +  +  ++  ++ +      ++   + +    +   ++  ++ +
+    + + ++ + +++++  + +  + +    +   + ++ + +++++
++++++ +    + +      +  + + +    +   +    + +
+    + +    + +      +   ++ +    +   +    + +
+    + +    + ++++++ +    + +++++    +    + ++++++

New depends: ply, jinja2

Rebase user namespaces patch on chromium 36.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>