Split out ejectors into their own module.

Also provide the throw utility, on both sides of the RPython/Monte line.

Signed-off-by: Corbin Simpson <cds@corbinsimpson.com> <simpsoco@google.com>
Split out collections.

Now lists and maps are in their own module. Additionally, a lot of stuff has
been forward-ported into these lists and maps, for programming convenience.

Signed-off-by: Corbin Simpson <cds@corbinsimpson.com> <simpsoco@google.com>
objects: Factor out and test CharObjects.

Chars are relatively simple; only a couple Unicode tests are needed to ensure
that they are working properly.

Signed-off-by: Corbin Simpson <cds@corbinsimpson.com> <simpsoco@google.com>