chore: use $ instead of jQuery inside gridster
feat(draggable): support horizontal scrolling while dragging
chore: rename calculate_positions to calculate_dimensions
feat(draggable): method to set drag limits dynamically
feat(gridster): increase grid width when dragging or resizing
Release v0.3.0
fix(gridster): resize.axes default option only 'both'

If passing resize.axes option it will be
what is defined and not ['x','y','both'].
fix(licenses): add required copyright message for underscore

Add the copyright message for the code taken from underscore as required
by the MIT license.
fix(readme): link title jsfiddle -> jsbin, edit 5) of process steps
feat(resize): add option to set min_size of a widget
fix(gridster): leaking options with multiple Gridster instances

`defaults` was being overwritten.

See [jQuery documentation](http://api.jquery.com/jQuery.extend/):

> Keep in mind that the target object (first argument) will be modified, and will also be returned from $.extend().
chore: Updated node package dependencies to work on clean system.

qunit->qunitjs and jquery 2.0 isn't listed in npm repository so
replaced it with the git location.
Release v0.4.0