Document How Module Names are Generated

[jcmartin]

This is related to #328. I could not find anywhere in the READMEs or documents as to how the module names are generated. It would be nice if this was explicitly spelled out in the README as one needs to know this in order to input it into the cabal file as part of generated-other-modules. If one does not input this in correctly, then not only will your imports fail, the files themselves will never be generated and as a consequence you are still left with guessing if you do not know the module name generation algorithm.