Rethink lambdas, datums, etc

[dvanhorn]

Starting with Loot the compiler should either return multiple values or a more structured result than just an Asm sequence so that compilation can be a single pass. The code would be more efficient and clearer and eliminate the functions that scan over a program and produce certain subexpressions (e.g. lambdas, datums).

[laelath]

so I was thinking about it, and I don't think there's any reason why the body of the lambda can't be put inline with the lambda creation site, as long as the creation path jumps around it. I won't deny that this feels pretty ugly though.

[laelath]

demoed in https://github.com/laelath/cmsc430-www/tree/inline-cc