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 Changes in v2.2.1 compared to v2.2.0
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bayliffe (1):
      Added calculation of difference between maximum and minimum of the properties, called using calc diff.

dprice (17):
      maxshapes increased to 32
      rendering in non-cartesian coords uses normalised interpolation if 3rd dimension is not a length
      Brio-Wu solution fixed!
      bug fix with exact solutions if time not read from file (now assumes t=0); also can specify shock position in mhd shock solution
      added page size option for 4KTV/Ultra HD
      implemented exact solution plotting on top of surface density/toomre Q/pdf plots
      bug fix with particle tracking of dark matter particles
      added Wendland kernels as options; reverted to usual definition of m5 kernel
      bug fix with projections if kernel radius changed via menu
      bug fix with axes printing if >1 plot per page, now more transparently handled
      better recognition of density and pressure columns in ascii read
      bug fix if multiplot read from defaults file refers to columns not present: now re-prompts for this
      minor fix to comment