use an interface + add docs
add a formatter that returns the raw image
add raw formatter
make formatters able to chain
add a formatter than can greyscale things
add the new formatter info
fix the then not returning the argument to allow chaining
use formatData to use the chain
fix the then chain to actually work
update doc
diversify
call the child
add a formatter to invert the image
Merge pull request #3 from Eluinhost/features/formatters

Formatter chains + new formatters