Add option for caching gCal events
We want to make it possible to run the script multiple times without burdening gCal API too much. That's why we want to cache calls somewhere for a day, and when the day is done, we make a new call. This makes it possible to have the script run more frequently, since we are only moving the red line up and down (mostly down).
When #1 is implemented, we would want an option that forced the script to clean the cache.
It might also be possible to cache the entire inner panel and the background wallpaper (depending on effect), and only move the red line for even quicker script runs. Might be a good advanced option.