Added check if input is disabled when setting the focus.

Setting the focus to a disabled element can cause an error in IE7 and
IE8.
Create bower.json
Merge pull request #15 from jhadenfeldt/master

Added check if input is disabled when setting the focus.
Make isBorderBox padding modification apply only to input elements
Merge pull request #16 from payalcsureja/patch-1

Create bower.json
Merge pull request #17 from burnsred/master

Make isBorderBox padding modification apply only to input elements
Merge branch 'master', remote-tracking branch 'upstream/master'