CVS commit by paolini: 

Added circular inversion of lines and circles (the button is
a merge of the three object types: InvertPoint, InvertLine,
InvertCircle).  Note that inversion is *not* a projective
transformation, so we cannot treat it like all other transformations.


  M +2 -3      ChangeLog   1.219
  M +2 -2      kig/kigpartui.rc   1.110
  M +2 -6      misc/builtin_stuff.cc   1.75
  M +39 -3     misc/special_constructors.cc   1.73
  M +8 -0      misc/special_constructors.h   1.31
  M +121 -2    objects/inversion_type.cc   1.2
  M +25 -1     objects/inversion_type.h   1.2