hdf5_ep

[svn-r6957] Purpose:
    Code cleanup & performance improvements

Description:
    Optimize hyperslabs that are built to detect situations where "regular"
hyperslabs can be recovered from span tree descriptions.

    Also, improve "same shape" routine to correctly work with all the different
combinations of selections.

Platforms tested:
    FreeBSD 4.8 (sleipnir) w/C++
    FreeBSD 4.8 (sleipnir) w/parallel
    h5committested