Just a few fixes to the Wiki pages:

- Removed old wiki system
- Remaining wiki is has been tidied up slightly, with new options to rich text editor and all pages ported to standard template theme
- More sensible URL scheme (e.g. /wiki/Main_Page)

We still need the actual articles written for it, but that will be sorted out soon too. In addition, there've been some minor tweaks to the Point Trading page, related to average price calculation and allowing any offer to be bought, even if over average price.