Better building for the three dists

[bigpresh]

It would be nice if we had a top-level build script that could be used to build, test, and release new versions of the shared core and D1 and D2 wrappers to save effort.

Also, running "prove" in the D1/D2 wrapper dists doesnt know to look for the shared core a level above, so if it's not already installed (and you don't manually set PERL5LIB or similar), it'll fail.