Issue: Extend Footnotes

Currently footnotes act very similarly to a URL tag. On Wikipedia, footnotes can be anything, and are usually not straight URLs.

Updated for the next build. FOOTNOTEs can include plain text and nested BB-Codes. The tag's option gives the footnote a name so that it can be reused via the same option elsewhere on the page. It is also now possible to define a number of columns for the reference list display by using an integer for the REFLIST tag's value.