Fix "spawn_enemy" not working in dev console
"Revive" the player when their saved HP equals zero

If the player exited the game when they were dead in Polymorphable,
their HP of 0 would be saved, causing them to die again when loading
their save. This patch fixes that.
Merge pull request #1288 from dorkster/devconsole

Fix "spawn_enemy" not working in dev console
Merge pull request #1289 from dorkster/hpmp

"Revive" the player when their saved HP equals zero