[WIP] Renamed an unused import. (Issue #48)
[WIP] Removed unnecessary NULL checks. (Issue #48)
[WIP] Improved code to dispatch the ISelectionChangedListener#selectionChanged() method. (Issue #48)
[WIP] Changed the RenamePHPElementAction class so that Rename Resource work in the PHP Explorer view. (Issue #48)
[WIP] Added the createRenameAction(IWorkbenchPart) method. (Issue #48)
[WIP] Improved the selectionChanged(IAction, ISelection) method so that the current RenameAction object always has the active IWorkbenchSite object. (Issue #48)