Performance Issue

[eladvider-softangible]

Hi, The way that the plugin work create a huge performance issue,

Saving the original text size cause the DOM to be change and its blocking operation, and cause delay to the loading (especially Chrome)

see https://developers.google.com/speed/docs/insights/browser-reflow

[boynet]

I solved it in my fork if you are interested https://github.com/boynet/open-accessability

I cant merge it because I made some other changes like replacing the icons with font-awesome and adding 2 new features (highlighted-headers and highlighted-links)