Add verbose option to log more messages on error returns

Some error returns from the WiredTiger library don't normally print out error messages, since they can happen in situations that are expected by the calling application. Occasionally it is very helpful in debugging a problem to know the specific source of an error code.

We could add a new verbose=[error_returns] configuration option, that would change the WT_RET and WT_ERR macro families to log a message if the error code is not WT_NOTFOUND or WT_ROLLBACK. The macros could start printing out line and file numbers along with the error code.