hdf5_ep

[svn-r24216] Purpose: Merged changes from trunk

Description from trunk, r22836
    In this bug, H5File doesn't have the ability to create attribute.  The
    following changes will provide that functionality and several others that
    were also missing:
    - Added an abstract class H5Location in between IdComponent and H5Object.
    - New class structure of IdComponent, H5Location, H5Object, H5File
                                IdComponent
                                     |
                                H5Location
                                /        \
                        H5Object        H5File
    - Wrappers in H5Object were moved to H5Location because the related C
      functions take either file, group, dataset, or named datatype ID.
    - Added wrapper for H5Rget_obj_type2
    - Added tests for file attributes and H5Rget_obj_type2 wrapper

Description from trunk, r22845
    Fixed miscellaneous inconsistencies and typos, which also took
    care of the failure in Packet Table test on daily test today.

Description from trunk, r24143
    Fixed comments, documentation, and mis-matched DOXYGEN_SHOULD_SKIP_THIS pairs.

Description from trunk, r24188
    - The failure in daily test was caused by missing initialization of member
    "id" in a few constructors.  This is now fixed.
    - Added two overloaded H5Location::setComment
    - Improved some error reporting in H5Location
    - Improved error reporting in tests

Description from trunk, r24189
    Changed header guards from single underscore to double underscore.

Platforms tested:
    SunOS 5.11 (emu)
    Linux/32 2.6 (jam)
    Linux/64 2.6 (koala)/PGI compilers