Missing image library in several content types

Hi,

I've noticed that the H5P server leaves out dependencies when exporting H5P packages: the versions of H5P.BranchingScenario, H5P.Column, H5P.CoursePresentation and H5P.InteractiveVideo that you can download from the Hub all don't include H5P.Image-1.0, even though they use it in the content! This means that the content won't be usable unless somebody has already installed the H5P.Image-1.0 library through another content type. This is a problem, as content won't work in several situtations:

1. There's a fresh install and the user only adds this single library. (S)he doesn't understand why images don't work.
2. The content is used in a standalone fashion like h5p-standalone by tunapanda. (no official support for this, so maybe Joubel doesn't worry about it too much)
3. In the future, Moodle will have the capability to insert H5P packages into text fields and. This will display content without actually installing the packages (similiar to tunapanda's approach I think). The content types mentioned above will be faulty then.

As number 3 is a real showstopper, I think the export functionality of the PHP server should be extended to include all dependencies used in the content. (I think the reason why Image-1.0 is not included is that it is not listed in the preloadedDependencies of any used library and thus not added.)