Update module/VuFind/src/VuFind/ILS/Driver/Aleph.php

Bugfix: Only convert month part from string to number if not already provided as number.
Error occures when input date has this format: 31/12/2013
Additional cleanup: Replaced deprecated split() with explode()
Streamlined and documented entity cleanup within stored MARC records.
Adding MultiBackend driver (VUFIND-643).
Decoupled resolver drivers from config reader.
Fixed resolver drivers to use HTTP client instead of file_get_contents; this adds proxy support and improves testability.
Started loading configurations through a custom plugin manager instead of static \VuFind\Config\Reader.
Use plugin manager instead of config\reader.
Merge branch 'master' of git://vufind.git.sourceforge.net/gitroot/vufind/vufind into bsbvf2