Merge pull request #701 from mcmonkey4eva/master

Pull request for the fixing of obscure issues
Add 'cause' context to on entity dies.
Check null for death without damage.
Merge pull request #702 from mcmonkey4eva/master

Pull request for needed functionality
add element.matches[regex], more meta work

- we apparently did not have a regex matcher for tags yet somehow
- more tag groups, yay