[OpenLayers-Trac] [OpenLayers] #878: Add "layerswitched" event to Layer and Control.LayerSwitcher

[OpenLayers]

#878: Add "layerswitched" event to Layer and Control.LayerSwitcher
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  Reporter:  openlayers  |       Owner:  euzuro     
      Type:  feature     |      Status:  new        
  Priority:  minor       |   Milestone:  2.5 Release
 Component:  Layer       |     Version:  2.4        
Resolution:              |    Keywords:  review     
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Comment (by crschmidt):

 * Add Layer Event
  * Remove noEvent from the code -- only used in LayerSwitcher, and no
 longer needed there
  * Add checkRedraw to LayerSwitcher -- called before redraw -- which
 returns whether a redraw is neccesary
  * Add LayerStates to LayerSwitcher for above. keeps track of visibility
 and name.

 Includes tests.

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Ticket URL: <http://trac.openlayers.org/ticket/878#comment:5>
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A free AJAX map viewer