Version 3.2.1: Z-scale bug fix

Z-scale fix 

• Well, this is embarrassing! Simon Scherrer recently pointed out that my mesh models where hilariously tall when applying a large z-scale. 
• Turns out that at one point I had done the z-scaling in one function, then forgot about it and applied it again in another function! 
• While easily fixed, this means that any z-scale larger than 1.0 was wrong (not sure since when, must be several years ...). For most users that's likely not an issue b/c it wasn't that obvious at low (>1.0) z-scales and many (including) myself have no real world experience with how a certain z-scale should properly  look like. (This is what convinced me that my old z-scale of 5 was WAY too much! Also, I like that they call the z-scale Boost factor!)
• Also, I think most user would have dialed in a appropriate z-scale  based on visual inspection. However, if you've been using TouchTerrain for anything scientific where proper z-scale matters you should account for my error and either correct your effective z-scale to the square of what you requested pre version 3.2.1 or re-do you model with the new (correct) z-scale method now in place. 

Old (pre version 3.2.1) z-scale of 5 aka Mordor mode!

Hillshaded relief with proper z-scale of 5

Fixed (>= version 3.2.1) z-scale of 5

• Again, thanks to Simon Scherrer for bringing this to my attention!