This contains a parallel Tupfile and Lua-Tupfile parser, and Lua versions of several test cases. The Lua Tupfiles use .lua as an extension. The helper built-in functions are also included. All Lua functions are in the "tup" table. As per Anatol's suggestion I tried squashing all the commits. It compiles, but I'm not sure I did it correctly and I'd be glad to redo it if requested.
Squash merge of integration_work branch.
Ah, I thought I had seriously messed up the merge/diff and somehow included a bunch of extra history. But it looks okay to me, I was just misidentifying some of the Lua source files.