Update python_bootstrap to 2.7.6

Python 2.7.x has *much* better cross-compiling support so that it's now
actually possible to properly cross-compile Python during the bootstrap.
Before, it would just depend a lot on luck and the build host used, now
it even cross-compiles on OS X.

This means it's now possible to build a working bootstrap image on OS X!
:)
x86_gcc2: Update haikuwebkit to 1.4.6-3.

Fixes breakage due to locale kit changes. Builds for x86 and x86_64
will be forthcoming.