(Update) Improve Linkify, escape special chars for BBcode

[Oha-you]

1. Fixes issues with < and > characters in BBcode. Currently this text:

   [size=13][b]Kanojo no Ura Sekai[/b] [i]<TOSHIRO SIDE>[/i][/size]
   

   Produces the following HTML:

   <span style="font-size: 13px;"><span style="font-weight: bold;">Kanojo no Ura Sekai</span>&nbsp;
   <em><toshiro side=""></toshiro></em></span>

   Notice the wrong <toshiro> tags.
   Also <span> inside <span> caused text to be big (wrong style removed).

2. Improves Linkify function.
   Current regex is outdated and doesn't work for domains with 4+ chars (like unit3d.site) because of [a-zA-Z]{2,3}.
   In general, finding and highlighting links is not a simple task, so it's better to use a dedicated package.
   I compared all modern ones and vstelmakh/url-highlight seemed to be the best. See examples.
   It works fine with existing urls, that's why it was necessary to put ->linky last after ->parse. Different order caused incorrect html.