* MangaMutiny - JsonNull fix
Some thumbnails and manga descriptions aren't maintained by the website.
This results in avoidable errors. Fixed with this commit.
* MangaMutiny - Increment extension version number
* Adding source Manga Mutiny
Webview doesn't work. Reason: it's an HttpSource based on an undocumented API - it's not based on web scraping
Credit:
- the concept for the Filter was taken from the MangaPark extension and changed to fit the circumstances
- the JsonObject extension function stems from stackoverflow
* MangaMutiny - multiple fixes
Moved mangamutiny to /src/en
removed "open" from class
changed if condition
