Add <&bs> - backslash tag

I had to rewrite a bitttt of the character escaping to allow this to
work, but it seems to all be fine. Also fixed a tiny mislabeled tag
meta.
More debug information in dB submit

Debug submit information will now begin with:
CraftBukkit Version, all plugins with versions, all loaded worlds and
all online players.
Fix location definition in scripts ran by 'Push'

If you PUSH an arrow into a mob, the arrow disappears before the script
is ran, so the location isn't recorded. This will record the last-known
location before collision.
Merge pull request #538 from mcmonkey4eva/master

Pull requests, yay!