Lazy loading

Lazy loading functions well enough to be merged and tested by a wider audience IMO.

This uses Karl M's public domain judy array, wrapped in my [judy array templates](https://github.com/mpictor/judy-template). If you do not clone that repo (`git clone git://github.com/mpictor/judy-template.git /path/to/stepcode/src/base/judy`), CMake will download and extract a tarball of HEAD in the proper location.

ctest results [here](http://my.cdash.org/buildSummary.php?buildid=439566) - all lazy loading tests pass

Like p21read, one lazy loading executable can be created for each schema. It is named similarly to p21read:
```
p21read_sdai_ap203e2_mim_lf
   lazy_sdai_ap203e2_mim_lf
```

In addition, a `lazy_test` executable is created that isn't schema specific. It doesn't have a registry, so it can't load instances. Its only use is in benchmarking, and I may (re)move it in the future.