Build system could be better

[LourensVeen]

The current build system has a few issues that I could fix, but I'd like to discuss first:

1. Dependencies aren't right, and the recursive make calls aren't either, so that incremental and parallel builds don't work.
2. Building is a two-step process, rather than a single make call
3. The binaries end up in dstar/, while it would make more sense to have them in the root
4. We're building starev in the root, is that actually part of SeBa or a leftover from Starlab?

It shouldn't take much work to fix this and I'd be happy to do so, but especially moving the binaries and removing starev changes things a bit, so I'd like to know if there are any objections to that first.