Integration/optional header problem

Currently `boostdep` will report as a dependency every include of every header it finds within an include folder. It would be nice if there was a way to tell `boostdep` that the header is optional, lets say with something like a comment line that contains `boostdep:integration_header`. To sanitize misuse of such headers they must not be included from other headers within a library that are not marked as well optional. When integration header is used from other libraries it is considered a dependency though, and the mark should be ignored.