fix(vboot_reference): mask vboot-9999

bad mistake unmasking this. Reset the mask.
add(sys-devel/sysroot-wrappers): Add new sysroot-wrappers tool.

This replaces the previous sysroot wrapper scripts that was bundled with
the Google toolchain. This one is implemented in a more generic manner
and based on ccache. Perhaps other custom wrapper scripts will
eventually move into this package as well.
Merge pull request #82 from marineam/wrappers

add(sys-devel/sysroot-wrappers): Add new sysroot-wrappers tool.
chore(coreos-installer): fixup the header details
feat(coreos-installer): install coreos- prefixed commands
fix(coreos-installer): fixup deps in -9999 ebuild

the verity package moved to coreos. Fix.
chore(coreos-installer): use the symlink style versioning
bump(coreos-installer): get the lastest version

this introduces the new coreos-setgoodroot code
bump(update_engine): use coreos-setnextroot