Try and fix memory errors reported from Valgrind.

The current allocation strategy is very naive. A pool or region
allocator should be employed to deal with Noah values, rather than the
current mess of keeping track of all the value and then bulk deleting
them at program termination (which isn't exception safe currently!)

At least the naive allocation strategy isn't riddled with Valgrind
errors anymore.
Merge branch 'master' of github.com:charlesturner7c5/noah