New key/talent binding: Autouse when below 50% life

[overgoat]

I think it would be super handy to be able to set certain talents like shields or heals to autocast when below 50% life. I find that most of my deaths when playing bump fighters are from getting click happy and not noticing how low I am until it is too late. The change of background color helps quite a bit, but in the late game one turn/click can be the end of a character.

[cttw]

Most heals take a turn, so beware. They are not always the best option in an emergency.

[Mewtarthio]

If you're below 50% life, you need to make every action count. That's exactly the last place you want to have an autouse talent.