* `if` function stack ordering is changed to use condition, if-false,
if-true (bottom to top). This is so we can pass a value on top of the
stack directly to a new `if` in a condition, so we don't have to store
a new value in a new variable.
* Add __splat__ and __minus__ functions to Int
* Add * and - builtins, which call the __splat__ and __minus__ functions
of the top stack item, respectively.
* Add factorial example because now factorials are possible with this
skeleton implementation, albeit a little hacky with the recursion.
Signed-off-by: Alek Ratzloff <alekratz@gmail.com>
