Transformation `raw` key does not work as documented

[howard-spoak]

Expectation

When using the raw key in the transformations parameter for getUrl, it's documented that the value will replace it entirely to allow for transformations such as image overlay.

Bug

raw- is prepended to the value that is included in the transformation, causing an invalid transformation string (ex: raw-l-image,...)

This is included in the test itself (see that the result has raw-w-200 in it), which seems like an oversight.