Replace HAVE_* by DEAL_II_HAVE_*

This replaces all of deal.II's internal configuration options and
definitions starting with HAVE_ by prefixed versions DEAL_II_HAVE_.

This won't go into the release (to little time to test thoroughfully).
Same here. I think you want to remove the `#ifdef` as well.

By the way, just so I understand this correctly: we now no longer check for the availability of individual functions any more, but only set `DEAL_II_WITH_LAPACK` if we found all of these functions?