common/hooks: add support for vcdiff creation
common/hooks: generate null diffs to the new files itself.
common/hooks: enable repackaging of indexes for xdelta
common/hooks: remove config variable enable vcdiff generation.
adobe-flash-plugin: update to 11.2.202.400.
chromium: update to 36.0.1985.143.
libidn: update to 1.29.
mpv: update to 0.5.0.
shorewall: update to 4.6.2.4.
screen: update to 4.2.1.
Merge pull request #503 from Gottox/xdelta

Generates binary diffs for repository indexes.
hooks/xdelta: style twerks.
xdelta3: make it a bootstrap pkg.
base-chroot{,-musl}: add xdelta3.
xbps-git: bump version (reposync vcdiff support by Gottox).
common/hooks: use cp instead of ln
common/hooks: use ln -f instead of cp
common/hooks: remove file before copy
common/hooks: delta creation: don't hide stderr
common/hooks: delta creation: only generate own delta for own XBPS_TARGET_MACHINE