Task sub split

This implements #175 (closed) While at it I also removed some dead code (including #174 (closed)) and cleaned up the linking of libraries in the Makefile. For some reasons we had still blas in lapack in there.

Finally I have also removed some commented-out old gravity stuff. That should make the diff for the gravity branch much easier to read when it becomes time to merge that in.

mentioned in issue #175 (closed)

Fixes #174 (closed) as well :)

Added 4 commits:

• 2f06ff6f...48ac97ea - 2 commits from branch master
• d8bf23e2 - Merge branch 'master' into task_sub_split
• 8df32afb - Update for sub self and pair tasks

Found a problem with partition.c which I've fixed (also merged to master). Otherwise all looks like a good exercise in hygiene so accepting.

Status changed to merged

mentioned in commit ca0eafb8