Fix bouncing scroll-down arrow bug in webkit

Webkit transform currently requires a vendor prefix. Without it, the arrow bounces and rotate to the original un-rotated state. See https://www.dropbox.com/s/46sjiihtjya42s8/wk-rotate.mov
Merge pull request #129 from Douten/patch-1

Fix bouncing scroll-down arrow bug in webkit
Optimize index.js and add style consistency

Declared all jQuery objects once where needed instead of diving into the DOM multiple times for the same object.

Added style consistency between variable declarations, if/else statements and functions.
Merge pull request #130 from jillesme/master

Optimize index.js and add style consistency
Fixes variable image width bug

closes #95
 - added onload event listeners to images
Merge pull request #132 from jeremija/image-width-fix

Fixed bug where image width changes on refresh
Merge branch 'master' of https://github.com/TryGhost/Casper