Implemented new layer persistence mechanism
 - Removed layer URIs
 - Removed catalog layer URIs
 - Catalog layer nodes now responsible for creating layers
Fixed the layer class instantiation so that it works with private default constructors
Removed saving of classname if uri is set
Added isGrandLayerSet() method to the ILayerDelegator
Fixed missing layer persistance if an error occurs during loading from a layer URI
Cleaned up activator
Externalized string
Added layer delegator awareness to the layer tree retrieval progress bars
Added checking if the layer implements IStatused, and if so returning the layer's status
Exported edit package
Replaced wmslayer:// layer with an editable WMSLayer
Formatting
Implemented reuse of Layer.sdef in sub-definitions
Updated to Sapphire 0.7.0
Refactored class names and fields to reflect changes in Sapphire 0.7.0
Initial commit of an editor for TiledImageLayers
Added support for importing TiledImageLayers from GeoTIFFs and other GDAL supported rasters
Replaced boolean array with AtomicBoolean
Added extension point documentation
Refactored getResourceURI* methods to return a URL instead of a URI