cf-dc-api.pl and cf-sketch.pl: always request backportPP backend
cf-dc-api.pl and cf-sketch.pl: always request backportPP backend.1
cf-dc-api.pl: change depends.os from a list of OR classes to a single regex/context
cf-dc-api.pl: handle depends.os and depends.classes to the runtime
cf-dc-api.pl: accept an array or a hash for the depends.os and depends.classes attributes
Old cf-sketch archive is not compatible with DC at all, better to remove it.
cf-sketch: README update