Fix the NOT instruction. Includes test case.

src/test/res/boolean.lua

@@ -0,0 +1,31 @@
+t = true
+f = false
+n = nil
+s = "Hello"
+z = 0
+one = 1
+
+print(t)
+print(f)
+
+print(not t)
+print(not f)
+print(not n)
+print(not z)
+print(not s)
+print(not(not(t)))
+print(not(not(z)))
+print(not(not(n)))
+
+print(t and f)
+print(t or f)
+print(f and t)
+print(f or t)
+
+print(f or one)
+print(f or z)
+print(f or n)
+
+print(t and one)
+print(t and z)
+print(t and n)