Merged revision(s) 25457 from branches/hdf5_1_8_13/c++/src/H5CppDoc.h:
Added a sentence suggested by Barbara to the Installation section. Part of HDFFV-8868 work. 

Tested: Doxygen and Firefox
The contents of this directory is the C++ Reference Manual and 
is generated by Doxygen.
BUg fix: HDFFV-8881

testfrome.c has incorrectly exit code (using -1). Fixed by replacing them
with C defined EXIT_FAILURE. Verified by temporary decreaing MAXNUMTESTS
to introduce failure in testhdf to see the changed code did work.
Also replaced all other correctly coded exit codes with the C defined
EXIT_SUCCESS and EXIT_FAILURE. This would help portability for non-Unix
systems.

Tested: h5committest.
some code refactoring to align trunk with VOL branch.

tested with h5committest.
Removed duplicate BIND(C) type defintion.

Tested: (jam: gnu, intel)
merge from trunk.