Revert production combination stuff.

This reverts commit 886b8aaab2d2134b137269b5871fa154040e402f and
32bd8b6b9f282ad7c7e905b9a0e78a4c9ec0ee53.
Readd the needed grammars back in.
Generating grammars now includes empty alternative
50 grammars (range 201 to 250) -- contains empty alternatives
Better README
Merge branch 'production_combinations'