upx: fix update-check
tinc: ignore update-check for pre-releases
task: ignore update-check for beta-releases
sg3_utils: fix update-check
opensc: ignore update-check for nightly builds
miniupnpc: ignore update-check for dated builds
replace nonfree=yes with repository=nonfree.

This way it is possible to set up package specific repositories for
i.e. specific devices.
move "repository" variable from environment/setup to environment/setup-subpkg
Manual.md: add documentation describing repositories and the repository variable.
common: fix "$repository" = "nonfree" comparision.
linux3.17: enable some forgotten/renamed modules.
linux3.18: enable some forgotten/renamed modules.
xbps: patch from master to make xbps-uchroot(8) bind mount recursively.
New package: busybox-static-1.22.1
busybox-static: define version/revision to make xbps-checkvers(8) happy.