Resize to fill function

[aweiland]

The function list is missing the "resize_to_fill" function from Blitline. Similar to Crop, but with a resize.

http://www.blitline.com/docs/functions#resize_to_fill

[chrylis]

Either a new function or one I missed on the first pass through. Adding.

[chrylis]

Added in v0.13.1. Note that in case you're using the Spring support, I'm likely to change the BlitlinePostbackHandler interface signature soon to resolve a compatibility issue with Spring Integration; if you don't throw any checked exceptions, you'll be fine. Note that the current code base would generally ignore them anyway, since there's little value in propagating them back to Blitline.