Showing the update status in the about dialog

[mhmd-azeez]

Right now, there is no way for the user to check if there are any new versions, or if an update is being downloaded. There is no need for a way for the user to invoke a check for update, because once per session is enough. But it would be nice for the user to know the state of the update process. There can be four such states:

• Checking for update: When the app has just started up and has no idea if it's the latest version or not.
• Downloading update: When the app is downloading update.
• Update Downloaded: When new updates are downloaded and the app is waiting for the user to restart it to apply them.
• Latest Version: When the app has checked for new versions and there are no new versions.