Fixed bSmallCaps() to use position_maps and actually work.

The SmallCaps() native scripting function as implemented was entirely worthless except for transforming any glyph it was given into a tangled mess at the baseline.  This was due to the fact that it did not populate a complete genericchange structure with position maps and a smallcaps structure.

This change enables minimal useful operation of SmallCaps() using the same values as appear by default in the small caps dialog box in the UI.