* Add a 'style' property to the layer.
* When a feature is added to a layer, either uses the style on the
layer, or uses the default feature style.
* Add test to Layer.Vector for this funcionality
* Adds a preFeatureInsert hook to change a feature *before*
drawing it.
* Change openmnnd demo to include the use of preFeatureInsert
and style attribute on layer.
git-svn-id: http://svn.openlayers.org/trunk/openlayers@2949 dc9f47b5-9b13-0410-9fdd-eb0c1a62fdaf
