add cache systems

[binsky08]

• add offline cache (can be disabled in settings)
• add an internal settings cache to speed up some things a bit

[animalillo]

Would it make sense to store the cache somehow encrypted? Perhaps forcing the users to set an app password lock or something like that to prevent possible information leak if another app or malicious agent manages to get access to the cache storage of the app.

I'm open to ideas and discussion on this topic, the cache system looks like a great feature!

[binsky08]

Would it make sense to store the cache somehow encrypted? Perhaps forcing the users to set an app password lock or something like that to prevent possible information leak if another app or malicious agent manages to get access to the cache storage of the app.

I'm open to ideas and discussion on this topic, the cache system looks like a great feature!

implemented a local storage encryption solution with #113