extend slickAdd and slickRemove functionality
Merge pull request #92 from MSamman/Slide-Management-Improvment-v2

extend slickAdd and slickRemove functionality
removes blue highlight on mobile swipe android
Merge pull request #93 from natewiley/highlight

removes blue highlight on mobile swipe android
Adding center mode
Finishing center mode. Adding docs.
Center mode demo update
Tweaking center demo