Fix netvar names for bomb events and use GetValueOrDefault.

Since the datatable update the names changed, and bomb events broke, so this is the fix

Also, I was wondering why you changed my code to use AbsoluteSquared? In 6d9fbec991303565002b15958b0f480aa7a9b928 you state that both are correct, but AbsoluteSquared does not account for the Z value.
It probably won't make a difference for bomb sites -- unless they are exactly on top of each other, which I bet some community maps would do. Then again, those would probably never be run through this library.