Make it easier to roll and expend hit die

[nschoenwald]

There are multiple features that that have you expend hit die - the healer feat, the arcane vigor spell and wither and bloom spell, just to give some examples.
It currently takes a lot of clicks and you need to be in edit mode to roll and expend hit die. It would be better if this was more user friendly and possible without entering edit mode, as it is something that regularly occurs during gameplay.