Update compiler (#22)

* refactor to use ast.Walk for recursive converting
* added lots of test cases
* added a new way to handle jump labels
* function calls with multiple arguments
* binary expression (LOR LAND)
* struct types + method receives
* cleaner opcode dumps, side by side diff for debugging test cases

pkg/vm/compiler/tests/array_test.go

@@ -0,0 +1,26 @@
+package compiler_test
+
+var arrayTestCases = []testCase{
+	{
+		"assign int array",
+		`
+		package foo
+		func Main() []int {
+			x := []int{1, 2, 3}
+			return x
+		}
+		`,
+		"52c56b53525153c16c766b00527ac46203006c766b00c3616c7566",
+	},
+	{
+		"assign string array",
+		`
+		package foo
+		func Main() []string {
+			x := []string{"foo", "bar", "foobar"}
+			return x
+		}
+		`,
+		"52c56b06666f6f6261720362617203666f6f53c16c766b00527ac46203006c766b00c3616c7566",
+	},
+}