add option to force load hidden images

[yoyurec]

in a project i have images in hidden tabs, so they are not rendered (b'cose of display:none)

ele.offsetWidth = ele.offsetHeight = 0

even when i used you public function load(item)

so it's a good idea to add an option to force them to load, like load(item, true)

[tomByrer]

Makes sense; mouse over effects & other animation.

[dinbror]

Implemented in version 1.3.0. Thanks for the sugguestion

[shinnn]

@dinbror How about adding force option to the Blazy constructor to enable this option by default? I'd like to always pass true to the second argument of Blazy.prototype.load on my project.

var blazy = new Blazy({
  force: true
});