Implemented EpisodeList class.

[DhanrajHira]

Bringing experimental branch up to date with my own fork. All further work will directly be done on the experimental branch.

Changes:

1. Implemented the EpisodeList, a convenience class that makes it simpler to get a particular episode from the returned list.
2. Modified the API to use the new EpisodeList class.
3. The 'Anime' and 'Episode' classes now store the episode list and 'AniwatchEpisode' values in a private property. This helps to reduce wait times.