Compiler update (#21)

* added seperate folders for cmd packages.

* Fix netmodes in test + reverse bigint bytes

* glide get deps

* add, sub, mul, div

* booleans

* strings

* binary expressions

* if statements

* function calls

* composite literals (slice, array)

* Added lots of test cases and update readme.

pkg/vm/compiler/tests/binary_expr_test.go

@@ -0,0 +1,72 @@
+package compiler_test
+
+var binaryExprTestCases = []testCase{
+	{
+		"simple add",
+		`
+		package testcase
+		func Main() int {
+			x := 2 + 2
+			return x
+		}
+		`,
+		"52c56b546c766b00527ac46203006c766b00c3616c7566",
+	},
+	{
+		"simple sub",
+		`
+		package testcase
+		func Main() int {
+			x := 2 - 2
+			return x
+		}
+		`,
+		"52c56b006c766b00527ac46203006c766b00c3616c7566",
+	},
+	{
+		"simple div",
+		`
+		package testcase
+		func Main() int {
+			x := 2 / 2
+			return x
+		}
+		`,
+		"52c56b516c766b00527ac46203006c766b00c3616c7566",
+	},
+	{
+		"simple mul",
+		`
+		package testcase
+		func Main() int {
+			x := 4 * 2
+			return x
+		}
+		`,
+		"52c56b586c766b00527ac46203006c766b00c3616c7566",
+	},
+	{
+		"simple binary expr in return",
+		`
+		package testcase
+		func Main() int {
+			x := 2
+			return 2 + x
+		}
+		`,
+		"52c56b526c766b00527ac4620300526c766b00c393616c7566",
+	},
+	{
+		"complex binary expr",
+		`
+		package testcase
+		func Main() int {
+			x := 4
+			y := 8
+			z := x + 2 + 2 - 8
+			return y * z
+		}
+		`,
+		"54c56b546c766b00527ac4586c766b51527ac46c766b00c35293529358946c766b52527ac46203006c766b51c36c766b52c395616c7566",
+	},
+}