Out of the oven now!  What happened:
	"rotate" is an existing function that rotates bits in elements of a vector
		There were also some syntax errors
	I got tired of \ for continuation
		There's a hack using a macro to quote things, but it's easier to just use a different file
		I used .c extension, since OpenCL basically lets you use c
	You can get the build log
		Not that hard really, just have to actually do it
		Note:  Some failures don't leave anything in the log at all!
	Points that miss the original, and rotating 90 degrees
	It can be helpful to put a dot for the rotation axis, in figuring out what's going wrong
		Obviously, rotation doesn't always include this
	Major blur effect:
		Comes down to rounding, fix that and it'll rotate ok even with just our simple sampling method
	Oddly enough, the only thing not wrong was the math!

Next:  Similarity at a particular rotation
	We'll need a separate kernel to reduce the results
	This sort of depends on the correct pole location

	Very simple similarity:  Sum of differences
		Doesn't take image features into account at all
		For exact alignment of very similar images, it can work