Allow NAPI to read generic HDF5 files
Allow NAPI to read generic HDF5 files

NXgetnextentry() returns "" (empty string) if no group information
is present. Passing "" or NULL to NXopengroup() skips the group check.
Together, these two modifications allow the nxbrowse application to
read a Matlab generated hdf5 file.

refs #24



git-svn-id: 1001b6e0dd469eaa302a741812f7f5d223cf35f7@855 ff5d1e40-2be0-497f-93bd-dc18237bd3c7

nexusformat/code,chrisemblhh/nexus,nexusformat/code,chrisemblhh/nexus,chrisemblhh/nexus,nexusformat/code,nexusformat/code,chrisemblhh/nexus,chrisemblhh/nexus,nexusformat/code