[CHANGES]

• Improved performance on perl 5.22 onwards, by merging the operation
  of the individual pp_fieldpad ops into the main pp_methstart op
  
• Prepare compatibility with core's use feature 'class':
  
  • Support field keyword as a synonym of has, though without
    immediate EXPR version
    
  • Merge meaning of ADJUST and ADJUSTPARAMS; give all such
    blocks a params hashref. ADJUSTPARAMS is now just a synonym
    
• Print "discouraged" warnings on requires keyword
  
• Print deprecation warnings on isa and does subkeywords
  
• Added list-returning ->get_attribute_values() accessor to
  Object::Pad::MOP::Field
  
• Deleted legacy XS symbols relating to "slot" from before it was
  renamed to "field"