Mark the symbol that is the name of a scope with the size of that scope

Mark the symbol that is the name of a scope with the size of that scope
(previously only the scope itself had that size).
Pass the size of symbols through the object file to the linker. Bump the
object file version and adjust object file reading tools (od65, ar65) to this
change.
Read the size in the linker and output it in the debug info.
Bump the minor version number of the debug info. Read the size and allow to
access it via the API. Do better version checking for the debug info and try
to be smarter when encountering unknown keywords to improve support for newer
minor versions.

git-svn-id: svn://svn.cc65.org/cc65/trunk@5057 b7a2c559-68d2-44c3-8de9-860c34a00d81