fix bug in class of cmtkreg objects

* and add test
make surface test self-contained
Fix longstanding bug in parsing cmtk warping registrations

* problem was when number of control points was divisible
  by 10
* also file should have been opened as text
Don't try and expand NULL path

* also change first argument to firstdir rather than dir
  (since this resulted in a complicated error to debug)
fix bug in mirror examples