Remove inline style of .dawandaWidgetContent

(this PR is a replacement of #2 because that one was not on a branch)

We are writing our own styles for the dawanda widget integration and disabling it was actually pretty simple with your code structure. I just did a DaWanda.Widget.prototype.renderCss = function() { return ""; };.

However while trying to do our own styling all the inline styles were pretty annoying, the one in this pull request in particular.