hdf5_ep

[svn-r19411] Purpose: 
 Add extra test cases for Bug1975 h5diff - support recursive comparison on group when specified as an object

Description:
 Merged from hdf5 trunk (r19409)
 Additional tests for combination of group recursive and --follow-symlinks 
 with multi-linked external links with several files (same name/strucure).

Tested:
 jam, amani, heiwa