table.io.omicron: fix benign typo
io.hdf5: minor edit
segments.io: fix segwizard cache reading
segments.io.ligolw: fix astropy opening files
segments.io.ligolw: fix ligolw cache reading
remove unused import
io.ligolw: fix astropy opening files
data.array: improvements to hdf I/O
segments.io.hdf5: HDF5 I/O added
io.hdf5: use native h5py file check