* Introduce the world-grain abstraction as a step towards a farmer.
* A few important cleanups and refactorings.
* better hush the build

* allow lisp modules with their own build-dependencies different from their parent.

+ shuffling code outside of main.lisp
+ a bit of farming

* start of a forker and farmer
* better error message when you forget to make your dependencies a list
* doc update

Also, clean up the driver.
Preliminary tthsum implementation.
Remove ";;;" from LICENSE.