lang: parser, funcs: Change the logical operators to OR, AND, NOT

This makes it easier to read for some, and easier to parse for us. This
also frees up more characters to use elsewhere.

examples/lang/map-iterator1.mcl

@@ -9,7 +9,7 @@ $mod0 = math.mod($now, 8) == 0
 $mod1 = math.mod($now, 8) == 1
 $mod2 = math.mod($now, 8) == 2
 $mod3 = math.mod($now, 8) == 3
-$mod = $mod0 || $mod1 || $mod2 || $mod3
+$mod = $mod0 or $mod1 or $mod2 or $mod3
 
 $fn = func($x) { # notable because concrete type is fn(t1) t2, where t1 != t2
 	len($x)