Add a chart-obj attribute to the directive to get a reference from the controller to highcharts
Merge remote-tracking branch 'upstream/master'

Conflicts:
	src/directives/highchart.js
renderTo was lost and chart could not render

Since dropping jQuery depedency in favor of angular.extend() it was not
possible to render a chart without specifying manually the renderTo
property. This was due to the fact that angular.extend() is not recursive
(whereas jQuery was).

To avoid adding depedency we merge manually the few properties.
Merge pull request #15 from Ecodev/master

Could not render chart without renderTo