Renamed LoadingIconFrameListener to ILoadingIconFrameListener
- Replaced the catalog browser's viewer content provider with one that updates automatically when children are added to the tree hierarchy
 - Changed the ILazyTreeNode interface so that it is responsible for providing nodes to display while it's loading
 - Added a general ILazyTreeNode mechanism for loading data using the retrieval service
 - Added animated loading icon to catalog browser
Fixed issue where, if a single catalog could not be loaded, no catalogs are loaded
Made the error node of a bad catalog removeable
Added catalog node delete handler
Made setting name/label more consistent from catalog to layer
Fixed selection handler on catalog browser when selecting multiple nodes
Added better setting of catalog node label when loading from a non file/url/uri
Added catalog dispatch handler
Moving catalog to top-level package structure (Issue #3)