Better garbage collection and special case handling.

- This version is able to handle the strict test environment (long Masonry
  transition duration)
- Switching between two channels that have the same videos (channel and
  all videos) now don't create ghost elements
Better garbage collection and special case handling.

- This version is able to handle the strict test environment (long Masonry
  transition duration)
- Switching between two channels that have the same videos (channel and
  all videos) now don't create ghost elements
- Shortened transition delay for "No new videos"
Merge branch 'master' of github.com:XrXr/YoutubeSubscriptionChecker
Merge branch 'master' into activities_checking