VM improvements, tests + bugfixes (#61)

* changed vm commands to match more of the standard

* fixed Uint16 jmp bug in VM

* moved test to vm + fixed numnotequal bug

* fixed broken tests

* moved compiler tests to vm tests

* added basic for support + inc and dec stmts

* bumped version

pkg/vm/test/numeric_test.go

@@ -0,0 +1,18 @@
+package vm_test
+
+import "math/big"
+
+var numericTestCases = []testCase{
+	{
+		"add",
+		`
+		package foo
+		func Main() int {
+			x := 2
+			y := 4
+			return x + y
+		}
+		`,
+		big.NewInt(6),
+	},
+}