install forever before progressing

Give the user the option to install forever before progressing
Update LaunchService.js
Update LaunchService.js
Update LaunchService.js
fixing console-err-printing
fix else error
fix else error
install forever if not available & start server right away
changed will to would

changed will to would in LaunchService.js
Merge pull request #11 from JahlomP/add-forever-install-when-not-avail

Add forever install when not avail