hdf5_ep

[svn-r11314] Purpose:
Bug #281

Description:
A dataset created in serial mode with H5D_ALLOC_TIME_INCR allocation setting
was not extendible, either explicitly by H5Dextend or implicitly by writing
to unallocated chunks.  This was because parallel mode expects the allocation
mode be H5D_ALLOC_TIME_INCR only.

Solution:
Modified library to allocate more space when needed or directed if the
file is opened by parallel mode, independent of what the dataset allocation
mode is.

Platforms tested:
Heping pp.