Function to copy an image.
Another option for get-ch-pixel; another macro to iterate over an image
Change of a namespace's nickname
First version of a faster convolution function

* Problems with primitive numbers.
Faster convolution

* The function to check the coordinates was taking too much time 
(number boxing).
Primitive array functions were moved to core
New name for functions to set and get pixels values
convolve function now accepts a collection as a mask