Do not resolve the lists of spans for LineInfos and Scopes, but keep them as

Do not resolve the lists of spans for LineInfos and Scopes, but keep them as
ids. This way, we can delay loading spans until we know that we definitely
need an object file.
Did some restructuring for writing of span lists to the debug info file.

git-svn-id: svn://svn.cc65.org/cc65/trunk@5261 b7a2c559-68d2-44c3-8de9-860c34a00d81