Request: operator[ ] for containers can be configured to emit an exception

[abailey-isi]

It would be wonderful if there was a way to configure ETL to emit an exception if accessing an out-of-range element of a container when using the operator [ ] instead of just the at( ) method.

e.g.

[jwellbelove]

I could maybe add an optional configuration macro similar to ETL_CHECK_PUSH_POP, maybe called ETL_CHECK_INDEX_OPERATOR