ufoLib's glyph draw() was passing outputImpliedClosingLine=False to
PointToSegmentPen(). This was causing incompatible nodes in
interpolatable tool for certain fonts, like this in NotoSansDevanagari:
Glyph dabhadeva was not compatible:
Node count differs in path 1: 23 in NotoSansDevanagari-Bold, 24 in NotoSansDevanagari-CondensedBold
Node count differs in path 1: 24 in NotoSansDevanagari-CondensedBold, 23 in NotoSansDevanagari-CondensedLight
Because a final lineto before a closepath was being elided or not in
some masters but not others. Wire up the parameter and control it
from interpolatable tool to fix this.