set far plane to 10000 to help with large models. probably still too small for truly ridiculous models, but at least now its consistent with other places where a single model is shown (eg spinner). fixes #1933
right shift zooms faster. left shift zooms fastest
add an alternate key cluster for keyboards without a numpad
turntable-style rotation
invert mouse
zoom with mouse wheel
fix the "alternate" keypad, I put it upside down
fix up the presets
Merge remote-tracking branch 'robn/modelviewer-fixes'