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/function_call_test.go

@@ -0,0 +1,61 @@
+package compiler_test
+
+var functionCallTestCases = []testCase{
+	{
+		"simple function call",
+		`
+		package testcase
+		func Main() int {
+			x := 10
+			y := getSomeInteger()
+			return x + y
+		}
+
+		func getSomeInteger() int {
+			x := 10
+			return x
+		}
+		`,
+		"53c56b5a6c766b00527ac461651c006c766b51527ac46203006c766b00c36c766b51c393616c756652c56b5a6c766b00527ac46203006c766b00c3616c7566",
+	},
+	{
+		"multiple function calls",
+		`
+		package testcase
+		func Main() int {
+			x := 10
+			y := getSomeInteger()
+			return x + y
+		}
+
+		func getSomeInteger() int {
+			x := 10
+			y := getSomeOtherInt()
+			return x + y
+		}
+
+		func getSomeOtherInt() int {
+			x := 8
+			return x
+		}
+		`,
+		"53c56b5a6c766b00527ac461651c006c766b51527ac46203006c766b00c36c766b51c393616c756653c56b5a6c766b00527ac461651c006c766b51527ac46203006c766b00c36c766b51c393616c756652c56b586c766b00527ac46203006c766b00c3616c7566",
+	},
+	{
+		"function call with arguments",
+		`
+		package testcase
+		func Main() int {
+			x := 10
+			y := getSomeInteger(x)
+			return y
+		}
+
+		func getSomeInteger(x int) int {
+			y := 8
+			return x + y
+		}
+		`,
+		"53c56b5a6c766b00527ac46c766b00c3616516006c766b51527ac46203006c766b51c3616c756653c56b6c766b00527ac4586c766b51527ac46203006c766b00c36c766b51c393616c7566",
+	},
+}