Don't allow dialogue if player controls are disabled.
Action::executeImp returns a bool value to indicate if the sound should be played.
fix FailedAction.
Implement "Rest Until Healed"

Fixes: https://bugs.openmw.org/issues/563
Remove debug printing from previous commit
Ouch, I used && instead of &, this broke actions without a sound
Removed dialogue fix again, now on separate branch
playercontrols switch now disables activation in general (Chris' suggestion)
Merge remote-tracking branch 'wareya/master' into next
Merge remote-tracking branch 'scrawl/bug_559' into next
Merge remote-tracking branch 'scrawl/bug_562' into next