Merge fixes from branch 'release-2.0.x'

* release-2.0.x:
  contrib: bump opendht
  opendht: fix windows and android build
  contrib/upnp: rename uuid_create to avoid conflict
  media: use rational class to carry framerate
  utils: add rational class

Change-Id: Ia2d25b2def85318968f881311d483cd785b0258f