Description:
    Merge 64-bit ID changes from branch to trunk.  (Plus a few minor cleanups
that aren't on the branch)

Tested on:
    Mac OSX/64 10.9.4 (amazon) w/C++ & FORTRAN
    (h5committested on branch already for a week)
fix HDFFV-8888 - H5Ldelete_by_idx fails on non-existent group name.

tested Jam. minor change.
merge from trunk.