refactor on("skill")

[earthiverse]

Changes:

• xrange is now used on all ranged skills
• curse is no longer boosted or limited to 200 range
• supershot's +20 range bonus is now reflected in design/skills.py
• revive only adds pdps if it's successful.
• skills that use a consume item can now be called without num in the request, it will search for the item in the player's inventory