Client Library Desires to Preserve an Error Stack Before It's Cleared:
Pre-conditions:
    - Client library has registered an error class ID and error information with
	HDF5 error API.
Scenario:
    - An error occurred after a HDF5 function call and there is another HDF5
    function call immediately follows. 
    
- To avoid the second HDF5 function call clearing the error stack from the
    failed(first) HDF5 function call, client library preserves it by converting it into
    object handle and clears the current error stack.  
Notes:
    - There are new API functions, H5Eget_current_stack and H5Eset_current_stack,
    to preserve and switch to current error stack.
Examples:
    - Switch Error Stack