feat(sointu, vm): implement pure-Go interpreter for bytecode

The old "native" compiler bridged version is now started with cmd/sointu-nativetrack,
while the new pure-Go bytecode implemented bytecode interpreter is started with
cmd/sointu-track

Thus, you do not need any of the CMake / cgo stuff to run cmd/sointu-track

vm/generate/generate.go

@@ -0,0 +1,47 @@
+// +build ignore
+package main
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/vsariola/sointu/vm"
+)
+
+func check(e error) {
+	if e != nil {
+		panic(e)
+	}
+}
+
+func main() {
+	outputFile, err := os.Create("opcodes.go")
+	check(err)
+	defer outputFile.Close()
+	fmt.Fprintln(outputFile, "// Code generated by go generate; DO NOT EDIT.")
+	fmt.Fprintln(outputFile, "package vm")
+	fmt.Fprintln(outputFile, "")
+	fmt.Fprintln(outputFile, "const (")
+	features := vm.AllFeatures{}
+	max := 0
+	for _, instr := range features.Instructions() {
+		if l := len(instr); max < l {
+			max = l
+		}
+	}
+	for i, instr := range features.Instructions() {
+		format := fmt.Sprintf("\top%%-%vv = %%v\n", max)
+		fmt.Fprintf(outputFile, format, strings.Title(instr), i+1)
+	}
+	fmt.Fprintln(outputFile, ")")
+	fmt.Fprintln(outputFile, "")
+	fmt.Fprintf(outputFile, "var transformCounts = [...]int{")
+	for i, instr := range features.Instructions() {
+		if i > 0 {
+			fmt.Fprintf(outputFile, ", ")
+		}
+		fmt.Fprintf(outputFile, "%v", features.TransformCount(instr))
+	}
+	fmt.Fprintln(outputFile, "}")
+}