MergeImageInfo command does not have any useful output

[lbussell]

The output of a successful run of the MergeImageInfo command looks like this:

READING MANIFEST
----------------

(from this build)

Surely there should be some additional diagnostic information we can log so that it's obvious the command is doing something. Some examples:

• List which imageInfo files were found in the input folder
• List which contents were determined to be out of date content and thus were removed
• Some output for each object that gets merged
• Writing the output to the disk