Fix select model element test.
Fix Formulas_FormulaCurve

Revit 2015 doesn't allow non-planar Nurbs curves. Not even in the hacky
way we could do them in 2014.
Fix test MAGN_3784

ElementTypes drop-down was not saved with the correct selection.
Changing it to ReferencePoint fixed a cast error in the test.
Fix InstParam sample tests.

Revit 2014 and 2015 returns different numbers of parameters in their
Family Parameters drop-downs. Saved index was off by two causing test to
pass in 2014 and fail in 2015. Replace drop down with string parameter
name.
Fix ScalableGraphFunctionTest

Geometry division logic changed. Test is now correct per design.