Feature/fix caching - Githubissues

Clears cache via webFrame.clearCache() on manual reloads in main window and preview window
Open preview window at currently active slide, by appending the index to the URL to be opened
Add name in packager config and set it to packageJSON.productName (such that the name of macOS .app file will be "Moonslide.app")
npm audit fix
Update version to 0.1.1-beta.X

moonslide-app / moonslide