This changes logic to allow more missed use cases of course_image to
work properly. The cases are:
. XML courses with the course_image attribute set
. Mongo courses that are imported without a contentstore
. Mongo courses that have course_image set but don't have a content store
It also exports default images_static_course.jpg to
images/static_course.jpg to handle a use case where a course author
uploaded an image to the default location in studio without using the
studio interface for adding course images, they then export the course, and then
import it without a contentstore
Factories were used when possible but tests depending on importing or things not manageable by factories used the toy course. New files were added to include the needed functionality. Most files are blank or have minimal xml needed to work
