Fix gravatar loading.
Fix gravatar loading.

- Also remove old requests from list when a new request for the same
  view can be fulfilled from the cache. Otherwise, the new image can be
  incorrectly overwritten by the loaded image later on
- Properly clean up list in case of an exception

Bloody-Badboy/gh4a,slapperwan/gh4a,edyesed/gh4a,edyesed/gh4a,slapperwan/gh4a,AKiniyalocts/gh4a,AKiniyalocts/gh4a,shekibobo/gh4a,shekibobo/gh4a,sauloaguiar/gh4a,DeLaSalleUniversity-Manila/octodroid-ToastyKrabstix,shineM/gh4a,sauloaguiar/gh4a,shineM/gh4a,DeLaSalleUniversity-Manila/octodroid-ToastyKrabstix,Bloody-Badboy/gh4a