hdf5_ep

[svn-r20945] Issue 4278 - When reading data fails, the error message should say which filter isn't registered.  This is the follow-up commit.  In my previous commit, I changed HDsnprintf to snprintf, which caused trouble for Windows because the name is _snprintf instead.  So I changed it back to HDsnprintf for properly defined macro.  I also changed all fprintf to HDprintf to be consistent.

Tested on jam - simple change.