fourth release

-add unit testing for feed repository
-add unit testing for feed usecase

third release

-fix issue in clear cache

• add dagger2 for the sample app

Second Release

what is new in this release

• support cancel all image loading tasks or cancel specific task
  -support configurable cache maximum
  -support adding place holder for image while loading it from remote source
  -support clear the cache

first Release

this release has core function for image loading with caching mechanism