fix content position balancing when moving selection over start position

When moving the selection over the start position of an element, Vex
should expand the selection to the end of this element. Instead of this
expected bahaviour, the selection was expanded to the end of the parent
element.

Change-Id: I8e20156131044569f3e4fc739d31cbee3b7c04b6
Signed-off-by: Carsten Hiesserich <carsten.hie@gmail.com>
2 files changed