hdfview

removed all references to GUI objects from H4/H5file and restored some functionality to H5File
restored item expand/collapse functionality to TreeView
restored save as hdf4/hdf5 functionality to TreeView
add equals method to HObject to correctly compare two HObjects
restored register/unregister fileFormat functionality to HDFView
worked on bug where TreeView can't open multiple HDF4 files correctly due to issue with HDF4 OID
fixed issue where closing the open file dialog crashes HDFView
fixed issue where files weren't being opened with the right access mode