Implement assert_nD in filter and feature packages
Allow assert_nD to take multiple dimensions
Use assert_nD in template.py
Fix syntax error
Fix syntax error and weiner check
Add docstring to assert_nD
Fix assert_nD call in template.py
Fix canny test to reflect new error type.
Make ndim explicit arg for clarity and update docstring
Catch a few more asserts
Add ndim argument in utility method
Merge pull request #1163 from blink1073/implement_assert_nD_array

Implement assert_nD in filter and feature packages