Fixing bugs in the parser

- Now handle mature tags as hidden tags properly
- Filter out invalid/broken site tags that would previously cause a crash
- Parser will now make sure it finds both the opening '[' and closing ']' to parse a tag, catches issues where users would use :[ as an emote.
When migrating to only saving the user's cookie I forgot to update checkLoggedIn
Download notification now opens the download manager

Some issue is going on with the open file intent and transdroid but for some reason it works through the download manager, so this is a temporary fix. You can now also click the download failed intents to be taken to the torrent that failed downloading.