Added change detection bin script (#459)

* minor bug fixes

* added ok and okm methods

* renamed okbm method

* removed unused imports

* better docs, np array inputs

* updated doc string to make types more explicit

* added applet

* this time for reals

* removed plot line

* added square step

* update args

* updated cd.py

* types

* more minor edits

* fixes and such

* updated notebook