[Therion] Updated Tutorial

I have just put an updated draft of my Therion Tutorial online (link on the Therion wiki), or click here: http://wscc.darkgem.com/footleg/therion/ I've completed lessons on area fills, and tackled the much more complex topic of how to structure your data for a project which is more than one scrap/survey trip. There are many ways to do this of course, but I have suggested one in the tutorial which should help people who do not already have a data model in mind. As always I welcome feedback and comments which will help me and others to improve and learn more. Footleg