Fix default path for zomicPP (gradle task).
Fix default path for zomicPP (gradle task).

* Fix zomicPP (gradle task) to use new folder-per-zomic-file directory structure.
* zomicPP task shows usage when invoked with no parameters.

david-hall/vzome-core,david-hall/vzome-core,vorth/vzome-core,vorth/vzome-core