Fix target not updating when holding down action button

Since we skip adding non-instant powers to the action queue if there is
already a non-instant power in there, we were skipping target
calculation.

This patch fixes it so that we update the target when trying to add
a power that is already in the action queue.
Fix segfault in WidgetListBox

Fixes #1195
Merge pull request #1196 from dorkster/fixes

Fix segfault in WidgetListBox
Merge pull request #1194 from dorkster/action_target

Fix target not updating when holding down action button