Rewrite of the creating mods documentation

I have rewritten the creating_mods.txt from the Phorum distribution to be more structured and have more info on writing modules. You can find the new documentation in the current development release of Phorum or on my development server:

dev version of creating_mods.txt

If you have comments on the updated docs, you can let me know here, so I can incorporate them in the documentation.

Looks excellent!

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-=[ Panu ]=-