Fix horizontal scroll of prompt

![before](https://cloud.githubusercontent.com/assets/1573141/4200023/de3631ae-380b-11e4-9bf9-38929ca3a8c5.gif)

When line of words in prompt is to long, horizontal scroll do not moving , when we type.
But it is moving on focus. Chrome have function `scrollIntoViewIfNeeded` which is
scrolling vertical and horizontal tabs so there is no need to do it. For other browsers
exists [polyfill](https://gist.github.com/hsablonniere/2581101). 
This code handles situations with horizontal and vertical scrolling.

This is how it works now:
![after](https://cloud.githubusercontent.com/assets/1573141/4200030/e98eefd2-380b-11e4-9a7f-9bc581f67dfe.gif)