Static interface type mismatch errors should be non-fatal

[anarthal]

Currently, when the static interface finds a type mismatch, no more packets are read, thus making further operations impossible.

Rationale: a static interface type mismatch means that a serious error has occurred. Either the type definitions must be updated (which needs rebuilding) or the database definitions are out of sync (can be solved by closing and re-opening the connection, as in a network failure).

However, this causes surprises. Following the principle of least surprise, it would be good to make these errors non-fatal.

See #211