update chocolateDoom to v2.1.0, chocolateDoomMaster removed
nodejs: disable usage of http-parser library on darwin, because it breaks the build
conkeror: upgrade to 141017 and use firefox for xulrunner
btrfsprogs: Revert update to version 3.17.

This reverts commit 249e4176778cf2bb39b92c2e84f387b73d0d0c9d.

Breaks snapper:

http://hydra.nixos.org/build/16420291

Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Merge pull request #4610 from MP2E/chocolate_doom_update

update chocolateDoom to v2.1.0, chocolateDoomMaster removed
sxiv: use giflib 5.0

https://github.com/muennich/sxiv/issues/180