This commit also removes the click listener, which was used for touch devices. The click listener will be added back when the lib will correctly handle clicks on touch devices.
When a style has no rules, the "else" symbolizers apply. When a style has rules and none of them apply to the given feature, the "else" symbolizers apply. Note that this is different than default symbolizer properties that might be merged into all symbolizers (as in OL2) - I don't think we should support that.
