enh: enabled extraction of a single energy-point in DOS
enh: enabled extraction of a single energy-point in DOS

This enables one to easily extract data from a single energy-point
instead of from all atoms and all energy-points.

Signed-off-by: Nick Papior <81a73bca3d342ffee33d7cf845fdbf77b6553831@gmail.com>

zerothi/sisl,zerothi/sisl