Merge pull request #23 from timsears/develop

changed shape to return Maybe Shape.
removed pesky asserts in Contours/Matching.hs
more changes to keep up with hmatrix015
lined up semantics of trapping/warning/preventing.
Merge pull request #25 from timsears/noassert

Noassert
first step adding Atan2 functions. edited functions.txt, ran
adapter.hs. Seems to require ippvm lib added to IPP_LIBS environment
variable. compiles but not yet tested.
implemented atan2 for images. works on whole image.
ned up traceShow