Fix netcdf eig

This branch changes the layout of netcdf output for an eigenanalysis. In addition to that, a few fixes (incorrect imaginary part of left eigenvector) and enhancements (labels, X0, joint.idx, joint.labels) are applied.

eig.step ## {step[0], step[1], ... }
eig.time ## {time[0], time[1], ... }
eig.dCoef ## {dCoef[0], dCoef[1], ... }
eig.idx

eig.0.Aplus
eig.0.Aminus
eig.0.alpha
eig.0.VL
eig.0.VR

...

eig.1.Aplus
eig.1.Aminus
eig.1.alpha
eig.1.VL
eig.1.VR

eig.idx
eig.labels
eig.joint.idx
eig.joint.labels

eig.0.step ## step[0]
eig.0.time ## time[0]
eig.0.dCoef ## dCoef[0]
eig.0.X0
eig.0.Aplus
eig.0.Aminus
eig.0.alpha
eig.0.VL
eig.0.VR

eig.1.step ## step[1]
eig.1.time ## time[1]
eig.1.dCoef ## dCoef[1]
eig.1.X0
eig.1.Aplus
eig.1.Aminus
eig.1.alpha
eig.1.VL
eig.1.VR