Added entity:attachments()

returns an array containing all of the attachment names pertaining to the given entity.
Modified for loop

Added setcost of 20 due to the use of a for loop. Also changed ipairs to a normal for loop.
whoops, forgot the v from the old loop

fixed v from the old loop with atc[i] from the current loop.
Added "ignore water" option to cam controller auto unclip

Fixes #727
Merge pull request #721 from OmicroNiuM/master

Added entity:attachments()