Change behaviour of the equality comparison in `ArrayIteratorBase`.
Rename `stop` as `end`.
Remove methods `end_range` and `end_subrange`.

They are not robust as a stopping criterion. We also incur a performance
overhead when we construct them. Instead using `it.end()` is better.
Syntactically, this is acceptable.
Rename `begin_range` as `begin_array`.

This seems more meaningful IMHO.
Rename `begin_subrange` as `begin_subarray`.
Fix unit tests for array iterators.
Fix image processing functions.
Remove debug comments.
Robustify unit tests for interpolation.
Remove extraneous header inclusion.
Fix Deriche filter.
Merge pull request #141 from DO-CV/fix-array-iterators-reaching-end

[BUG] Fix array iterators reaching end.