Latest changes. Work in progress
Nav generation seems to be correct, at least for case of type='toc'
Adjusted debug messages.
Added doDebug parameters, missing namespace decl
Use navigation keys for manifest item IDs when possible
Use key for itemref in spine
Corrected calls to getTargetUri() to specify the map URI. All nav and link generation appears to work
Corrected namespace of generated nav element
Added 'missing graphic' files to use when an image reference can't be resolved
Copying and inclusion of CSS files in the EPUB is correct. References from topics are wrong