Adding a context menu class name to dropdown

[walexy]

It could be useful to some to target the dropdown by adding a contextmenu class to $contextMenu.addClass('dropdown clearfix');

Something like $contextMenu.addClass('contextmenu dropdown clearfix');

That way a designer can apply styles to the context menu without affecting other bootstrap dropdowns. Thanks for the the great plugin.

[josetaira]

e2f1dbb now adds the class angular-bootstrap-contextmenu to the dropdown. README has also been updated accordingly.