Pine needs internet access to work (which it shouldn't)

[fosple]

Current behaviour

• Pine tries to connect to the internet to load files in order for it to work (KaTeX library)
• KaTeX is not included in Pine binary (see https://github.com/lukakerr/Pine/blob/master/Pine/Models/HTML.swift#L60 )

Desired behaviour

• Include all required libraries in the application so Pine does not have to load code from a 3rd party
• KaTeX has a MIT license, so it should be legally possible to include it in the app (https://github.com/KaTeX/KaTeX/blob/master/LICENSE)