Missing genre key causing error

[salmanm2003]

Hi @mfelczak,
I have noticed that the missing genre key is causing an error, as the key SUBMISSION is hard-coded as below:

bepress/BepressImportDom.inc.php

Line 740 in a679ba6

$genre = $genreDao->getByKey('SUBMISSION', $this->_journal->getId());

I could fix it by passing the custom key as a parameter:
php tools/importExport.php BepressImportPlugin journal username editorUsername defaultEmail importPath genreKey
Please let me know if this approach is ok for you, so I can send a PR?