remove animation and switch to good ol' manly jQuery append

I guess the animation is not the problem: I once moved [the focus recovery](https://github.com/finnlabs/angular-context-menu/blob/master/src/angular-context-menu.js#L120-L122) out of the animation promise (see https://github.com/finnlabs/angular-context-menu/commit/ee06674218ec31480427ae2822bac26cfb71a32d). We may should put the recovery back there again.