Comparison of Two RTPlan Objects from ARIA and RayStation

[rabayliss]

• Handle the following cases:
  *Electrons w/wo Bolus
  *VMAT
  *3D
• A general purpose function that compares stuff, with logic for finding nested items
• A dictionary that manages the details of the comparisons: parameter, date type, whether we expect an exact match or approximate (allowing rounding errors, for example