v2.3.0

Major changes:

• DOS energies are no longer shifted by SIGMA in smeared calculations;
  this will cause the DOS line to extend slightly beyond the VBM, but
  will ensure peaks are in the right positions. (@yw-fang & @ajjackson)

New features:

• Fermi level may be chosen as energy zero in DOS or band structure (YWF, AJJ)
• Horizontal line may be requested at energy zero in DOS or band structure (YWF, AJJ)

Bugfixes

• VBM shift argument was not correctly passed in DOS plots (@pzarabadip)
• Scissor option with combined band and DOS plot did not scissor DOS (@utf)
• Spin option with combined band and DOS plot did not apply to the DOS (@utf)
• Fixed phonon band structures with non-analytic correction (@utf)