Merge README and demo from master
Merge readmore.js from master.

Added a 'transition end' event listener to accommodate the afterToggle callback option.

May need some additional cross-browser work.
Modified plugin initialization and style injection to work with multiple Readmore instances

The 'speed' option can vary from instance to instance. This change allows that variation, rather than only using the first speed setting from the first instance.
Fix toggle selector in injected styles
WIP - status unknown