hasse cache
+ Started on a caching system. Right now it only caches API Data, not pictures
+ Added a setting to change the TTL of the cache data
+ Added a refresh button (which doesn't override the cache, though)
* Translated Picture Upload dialog to be more consistent with the rest of the UI
* Meal Detail fragment always shows the latest picture instead of a random one
* Sigfood API: SigfoodApi is now serializable, and has a field for the date
  of the call
hasse layout
+ Added bar at the bottom of the menu, showing the last refresh
+ Added a message when there's no food on a day instead of just displaying an
  empty page
* Refresh button in action bar now reloads the menu even if there's a cache
* 2-column meal layout only activates on width > 800dp now
* Menu does not reload if there is a cache and
  there is no internet connection
* Header now changes the date instantly when buttons are pressed
+ Added an About section, mainly to find a place for the required Apache license
+ Changes to PictureThread: Cached images, now handles meals with no pictures
* Menu now shows the latest image for each meal
* Error images are now the same width as food images
* Fixed a crash when starting Sigfood
* Reduced picture cache lifetime from 7 days to 1 day
* App now cleans cache in onDestroy
* Fixed a bug where switching back and forth between two days
  would desync date in header and the true menu date
* A bit of cleaning up in HttpMultipartClient
+ Added the ability to keep scrolling while a menu loads. This will skip
  weekends, and can only scroll up to a week into the future. If there is more
  menues than that, the user will have to wait for it to load.
* Allowed SigfoodThread to stop between the cache check and the API call
* Loading icons now cover the height of the picture being loaded, to avoid
  menues jumping around as images appear. The same was done on meal pages, but
  only reduced the jumping instead of eliminating it because of different
  pictures having different aspect ratios
Externalized Strings + English
* Externalized all strings which were hardcoded and are not overwritten by the
  code (for example, placeholders for meal names)
+ Added an English translation, which will be used on non-German devices
o TODO: Do not automatically set language. Have German as default and English
  as an option in the Settings.
Merge pull request #5 from Suyooo/master

Cache