Hello,

When running ERT tests in batch mode, the conservative values
chosen for `print-level` and `print-length` sometimes make it
difficult to see what exactly is wrong.  This patch introduces
two new variables (`ert-batch-print-level` &
`ert-batch-print-length`) that one can use to customize them;
e.g.

    emacs -batch -l ert -l my-tests.el \
          --eval "(let ((ert-batch-print-level 10) \
                        (ert-batch-print-length 120)) \
                    (ert-run-tests-batch-and-exit))"

Please let me know what should be changed.