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/fns.sex

@@ -1,10 +1,10 @@
 ;;; Prototypes
-(fn void puk ())
+(fn puk () void)
 
-(pub fn void plak ())
+(pub fn plak () void)
 
 ;;; Functions
-(fn int foo () (return 1))
+(fn foo () int (return 1))
 
-(pub fn void bar ((int a) (int b))
+(pub fn bar ((a int) (b int)) void
   (printf "%d\n" (+ a b)))