hdf5_ep

[svn-r113] Added mechanism for reference counting IDs.  This is to facilitate sharing
an ID between multiple interfaces in memory.  Changes included adding a
parameter to the H5Ainit_group call for the function to call to free the
structure associated with an ID when its reference count drops to zero and
two new function calls: H5Ainc_ref & H5Adec_ref which increment and decrement
the reference count of IDs.  Its still possible to call H5Aremove_atom on
a ID with multiple references, leaving dangling IDs in memory...