Fixes from base elevate-zoom-plus (v.1.2.2) library:
- CORE: lots and lots of code quality improvements (thnxs Gregor Adams !!!)
- FEATURE: add option to gallery swap event (thnxs shrpne)
- FEATURE: added custom zoomContainer (thnxs David Rosendo)
- FIX: properly remove event handlers on destroy (thxs shrpne)
- FIX: IE 11 compatibility (thnxs Michael Thessel)