message: Prepare changelog for v0.8.8
diff: +Changes in [0.8.8](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.8.8) (2017-04-25)
  +===================================================================================================
  +[Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.8.8-rc.2...v0.8.8)
  +
  + * No changes
  +
  +
  Changes in [0.8.8-rc.2](https://github.com/matrix-org/matrix-react-sdk/releases/tag/v0.8.8-rc.2) (2017-04-24)
  =============================================================================================================
  [Full Changelog](https://github.com/matrix-org/matrix-react-sdk/compare/v0.8.8-rc.1...v0.8.8-rc.2)
  