Change text formatting to HTML

[rizaumami]

Markdown text formatting is simpler than HTML, but it's hard to escaped.
The use of Markdown in ThorsHammer is prone to error, i.e when in need to print user name that contain unpaired Markdown tags, e.g si_kabayan or ._..

The HTML itself is not actually bullet proof to this kind of weird names (there is exist names thats contains unclosed < or > tags), but IMHO, it's easier to escape.

So, I propose to change the text formatting from Markdown to HTML, or provide a function/libs to reliably escape the tags.