0.9.5

• Changed difference objects to make them hashable (can now be used
  as set members or as dict keys).
• Added __slots__ to difference objects to reduce memory consumption.
• Changed name of Selector class to Select (Selector now deprecated).
• Changed language and class names from allowed and allowance to
  accepted and acceptance to bring datatest more inline with
  manufacturing and engineering terminology. The existing allowed
  API is now deprecated.