Photon: Medium-large size not Photonized

[kraftbj]

Looking at a media endpoint, most of the URLs are Photonized except for the medium-large size. This is a relatively new size introduced in 4.4 and is generally hidden.

https://kraft.im/wp-json/wp/v2/media?parent=33887
Medium (and other sizes): https://i0.wp.com/kraft.i….jpg?fit=400%2C400&ssl=1
Medium_large: https://kraft.im/uploads/1476493169-768x768.jpg

[kraftbj]

Should be pretty straightforward. I think we need to update https://github.com/Automattic/jetpack/blob/master/class.photon.php#L864 to include the medium_large size. Option names can be found https://github.com/WordPress/WordPress/blob/8ed022b568475672b0b18985b687da21af11ee19/wp-includes/media.php#L83