Auto-check eggs for update

[Boy132]

Adds a new command to check installed eggs for updates. This just fetches the json from the update_url and compares it with the current json. (or rather the hashes of the json files) It runs automatically every hour.

If an update is found it will also display a button on the eggs list that will simply re-import the updated egg json.

This will also mean that if you edit an egg it will detect it as "outdated"!