Refactor how the models.

- They now have a common base class.
- They no longer inherit from ParseObject as that wasn't allowed by Parse's SDK.

Signed-off-by: Aron Cedercrantz <aron@cedercrantz.se>
Merge branch 'master' of https://github.com/Triple-A/Hemmafesten

* 'master' of https://github.com/Triple-A/Hemmafesten:
  skit
  sökfunktion med oklickbara resultat