ignore single relative moveTo's (like with anchors)

If a glyph has anchors and components, stacking single relative
moveTo's will end up in a wrong relative point. Pens like the
t2CharStringPen depens on relative points and since they jump by the
relative anchor position basePen decomposition will not work.
rename attribute as an existing subclass already uses this...
Merge pull request #2 from typemytype/master

ignore single relative moveTo's (like with anchors)