Description:
    Merge changes that correspond to the 64-bit ID changes (without the actual
switch to 64-bit IDs) to the 1.8 release branch.  (Plus a few minor cleanups
and alignments with the trunk 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)