fix #959

- fixes #959 by renaming "nw.exe" to "Popcorn Time.exe"
- Removes app.ico from main dir (it's already present in src/app/images/popcorntime.ico)
- Adds a shortcut in main dir to launch from there if the user deleted the others (from desktop and start menu)
- Removes "Start Popcorn Time" from shortcut commentaries and replace it with "Popcorn Time" for internationalization ("start" is english-only)