Prevent adding a module if it's already in the list.
Because on some systems it's not possible to define environment variables, you should be able to add the module to the normal module list (defined at the top of this file). Problem occures when you work with different systems for dev/test/prod etc. and want to share the same code base.

For the Aleph Driver, it's possible that the item ID (id from route) and the holding ID (id from query) are different. With the += operator for merging, the id attribute from $keyValueArray was not used and an invalid REST url was sent to the ILS.
I'm not sure why the record id is loaded from the route here. With this fix, it's only used as a fallback when not defined in the query as a HMACKeys-variable of the ILS.

Aleph uses id:item_id which causes the conflict here.

This might deserve its own class if it ever needs to be reused in the future.

Note: this will create some inefficiency until \VuFind\Config\Reader is factored out of code; in some cases, configurations will load twice.  Should be sorted out soon.

Created getConfig convenience method in base controller; used this to eliminate several Config\Reader calls.

Simplified some method signatures thanks to the new dependency injection approach.
Decoupled ILS\Logic classes from Config\Reader.

Created class for managing holds configuration; eliminated some static calls/methods and a circular dependency.

Created mailer factory to better separate VuFind-specific configuration issues from actual mailer functionality.

Started loading configurations through a custom plugin manager instead of static \VuFind\Config\Reader.

Fixed resolver drivers to use HTTP client instead of file_get_contents; this adds proxy support and improves testability.

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()