Move post/thread regex patterns to separate file

[eksopl]

Move the regexes hardcoded in the source code to a separate regex file.

Perhaps with a script that either generates said file from fuuka. Either that, or make fuuka also be able to read the regex definitions from the same file.

[oohnoitz]

II believe all of the regex patterns are now back in the Yotsuba.java file again and I'm not sure if it will be separated again.

Anyway, is it possible to have all of the regex stored outside like the JSON settings file as well? It would allow us to make small tweaks to the regex when necessary without recompiling asagi.