RF: PDist2Target -> PDistTargetSimilarity

Few more characters for improved clarity
Merge branch 'master' of github.com:PyMVPA/PyMVPA

* 'master' of github.com:PyMVPA/PyMVPA:
  BF(PY26): define assert_is_instance for python < 2.7
  TST: unittest for @with_tempfile
  RF: use @with_tempfile to generate temporary directory
  BF: ensure that files are not matching, even if there is an "x" in the randomly generated prefix of a temporary file
  NF: unit test for afni_suma_spec
  ENH: remove "print" statement showing which surfaces where generated when adding new views to spec file