Fix windows launcher (#255)

* Add Windows launcher

The launcher looks at directory "Versions" next to its executable.
It finds the latest version and runs the executable in that directory
with the same name as itself. For instance:

  Aminal.exe <- the launcher
  Versions/
    1.0.0/
      Aminal.exe
    1.0.1/
      Aminal.exe

In this example, running the top-level Aminal.exe (the launcher) starts
Versions/1.0.1/Aminal.exe.

Having a launcher allows Aminal to be updated while it is running. For
example, version 1.0.1 could be downloaded without disturbing running
instances of Aminal 1.0.0.

* Implement a command-line installer for Windows

It can be generated with the Make target installer-windows.
It requires that you ran Make target launcher-windows before.

* Implement Uninstaller for Windows

* Codesign Windows auto-update executables

* Don't require Admin privileges for Win uninstaller

* Remove references to fman

* Explain automatic updates in windows.md

* Limit installer go packages compilation only to Windows platform

* Fix Windows launcher

* gofmt for launcher.go

Makefile

@@ -78,7 +78,8 @@ launcher-windows: build-windows
 	if exist "bin\windows\Aminal" rmdir /S /Q "bin\windows\Aminal"
 	mkdir "bin\windows\Aminal\Versions\${VERSION}"
 	go build -o "bin\windows\Aminal\${BINARY}.exe" -ldflags "-H windowsgui" "${GEN_SRC_DIR}\launcher"
-	copy ${BINARY}-windows-amd64.exe "bin\windows\Aminal\Versions\${VERSION}\${BINARY}.exe" /Y
+	windres -o aminal.syso aminal.rc
+	go build -o "bin\windows\Aminal\Versions\${VERSION}\${BINARY}.exe" -ldflags "-H windowsgui"
 	IF "${WINDOWS_CODESIGNING_CERT_PW}"=="" ECHO Environment variable WINDOWS_CODESIGNING_CERT_PW is not defined. & exit 1
 	signtool sign /f windows\codesigning_certificate.pfx /p "${WINDOWS_CODESIGNING_CERT_PW}" /tr http://sha256timestamp.ws.symantec.com/sha256/timestamp bin\windows\Aminal\${BINARY}.exe
 	signtool sign /f windows\codesigning_certificate.pfx /p "${WINDOWS_CODESIGNING_CERT_PW}" /tr http://sha256timestamp.ws.symantec.com/sha256/timestamp /as /fd sha256 /td sha256 bin\windows\Aminal\${BINARY}.exe

windows/launcher/launcher.go

@@ -23,10 +23,12 @@ import (
 	"io/ioutil"
 	"os"
 	"os/exec"
+	"os/user"
 	"path/filepath"
 	"sort"
 	"strconv"
 	"strings"
+	"syscall"
 )
 
 type Version struct {
@@ -42,8 +44,23 @@ func main() {
 	versionsDir := filepath.Join(executableDir, "Versions")
 	latestVersion, err := getLatestVersion(versionsDir)
 	check(err)
-	target := filepath.Join(versionsDir, latestVersion, executableName)
-	cmd := exec.Command(target, os.Args[1:]...)
+	usr, err := user.Current()
+	check(err)
+	cmd := exec.Command("C:\\Windows\\System32\\cmd.exe", "/C", "start", "Aminal", "/B", executableName)
+	cmd.Dir = usr.HomeDir
+	latestVersionDir := filepath.Join(versionsDir, latestVersion)
+	path, pathSet := os.LookupEnv("PATH")
+	if pathSet {
+		path += ";" + latestVersionDir
+	} else {
+		path = latestVersionDir
+	}
+	cmd.Env = append(os.Environ(), "PATH="+path)
+	const CREATE_NO_WINDOW = 0x08000000
+	cmd.SysProcAttr = &syscall.SysProcAttr{
+		HideWindow:    true,
+		CreationFlags: CREATE_NO_WINDOW,
+	}
 	check(cmd.Start())
 }