Update License to year range

Updated license to present year (2014).
ie 11 DocumentFragment doesn't have .children field, use .childNodes instead

fragments[i].children was undefined in iexplore 11.0.9600.16521
Merge pull request #68 from naman34/patch-1

Update License to year range
Merge pull request #72 from rnzo/master

ie 11 DocumentFragment .children undefined, use .childNodes instead
Update README.md
Update README.md
Added Gitter badge
Merge pull request #107 from gitter-badger/gitter-badge

Add a Gitter chat badge to README.md
"Balanced columns" algorithm

This commit include a new algorithm that handle elements height during
the repartition of the items.
The previous algorithm was pretty simple (just balance same amount of
items in each columns), and this can create visual issue if lots of
items have different heights.
I currently have an implementation that can use more than 5000 items, &
with this amount the differences are too big. Checkout an ![commented
example](http://cl.ly/image/1c0N2o181932/Screen%20Shot%202014-03-20%20at
%2021.53.23.png)

Here is a new algorithm that include a small process to retrieve
correct height (by appending them in a additional column
showing/retrieving value/removing ). Using a wrapper to append & remove
from the dom make this very fast. I don’t get any lag with lots of
items on my current board.

Should close #4 (& so close #52 )
Fix latest Chrome issue (Chrome 33)

Simple requirement added
Close #69 #40
Fix documentfragment `children` issue

That issue was spotted on Safari 7