compiler: Make maps and lists able to look up their params

As a neat syntactic sugar, it's very neat if maps and lists are able
to work as if they were functions, and look up their arguments.

This implements just that, by translating (map key) to (index map key)
internally, and (list idx) to (index list idx).

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>
Removing some trailing space (cosmetic)
Adding @algernon to AUTHORS.