Remove list() calls from for loops.

It's unnecessary to create a list out of an iterable, if you are in fact
only going to iterate through it!
Remove list() calls in container membership tests.

Container membership tests understand iterables.
Remove list() calls in map() calls.

map() can handle iterables.
Remove some more list()s where they aren't needed.

Either used as iterables, or in places they'd be iterated through
anyway.