[glyf] add 'padding' attribute to glyf table; assert is in (0, 1, 2, 4)
[glyf] add 'padding' attribute to glyf table; assert is in (0, 1, 2, 4)

The default (1) keeps the current behaviour (i.e. only pad when we can
use short offsets). Optional values are 0 (no padding), 2 and 4.

googlefonts/fonttools,fonttools/fonttools