Prefer sources with the origin "Pragmatux" too

Enhance the preference added in 31d6638.
Revert to emdebian's squeeze repository for cross-toolchain

Emdebian's wheezy repository isn't a reliable source for a
cross-toolchain. Some bits of gcc-4.7 seem to get mixed in if you
install gcc-4.4. Symlinks, paths, and pkg-config seems a little
squirly with gcc-4.7.

For now, revert to the gcc-4.4 cross-toolchain from the squeeze
repository.
Add changelog entry for 2.2