Downgrade design support library (fixes #580).
Downgrade design support library (fixes #580).

Looks like Google fucked up the lib and is using a dependency
that's not available before 5.0

flipreverse/syncthing-android,flipreverse/syncthing-android,begetan/syncthing-android,jmintb/syncthing-android,syncthing/syncthing-android,lkwg82/syncthing-android,Nutomic/syncthing-android,Zillode/syncthing-android,Zillode/syncthing-android,syncthing/syncthing-android,wweich/syncthing-android,wweich/syncthing-android,Nutomic/syncthing-android,syncthing/syncthing-android,jmintb/syncthing-android,begetan/syncthing-android,lkwg82/syncthing-android