move Sex to better types

Types, fns and vars are now written in another, better, more intuitive
and readable way.

Types:
"pointer to const char" is "* const char"
"array of pointers to volatile int" is "[* volatile int]"
Read left to right

Vars (as well as fn args, struct fields):
(var name type)
(struct vec3 ((x float) (y float) (z float))
(fn vec3-add ((v1 vec3) (v2 vec3)) vec3 ...)

Also fns are now have return types after arg list.

* is now must not be attached to any type name (or variable for that
matter)

example/hello-world.sex

@@ -1,9 +1,9 @@
 (include stdio.h)
 
-(pub fn int main ((int argc) (char **argv))
+(pub fn main ((argc int) (argv  [* const char])) int
   (puts "Hello from Sex!")
-  (var (array char 512) name)
+  (var name [char 512])
   (puts "What is your name?")
-  (scanf "%s" (cast char* &name))
+  (scanf "%s" (cast (& name) (* char)))
   (printf "Hello, %s!\n" name)
   (return 0))