This introduces:
* new syntax for list literals, put comma-separated values between
braces for your new list
* new syntax for indexing, do `foo[index]` to get the value in `foo` at
`index`. Lists also allow negative indices too. Any type that wants to
be indexed can include their own __index__ function as well.
* new VM instruction, BuildList. List literals were a lot easier to
implement using this rather than creating a new list, creating a
temporary stack value, and then duplicating + pushing to that
temporary value over and over.
Signed-off-by: Alek Ratzloff <alekratz@gmail.com>
