TABLE: removed duplicate dxf_table_appid struct definition.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
TABLE: changes in Doxygen comments.

Signed-off-by: bert <bert.timmerman@xs4all.nl>
TABLE: corrections in dxf_table_write_tables().

Signed-off-by: bert <bert.timmerman@xs4all.nl>
TABLE: initialise pointers to symbol table entries.

Signed-off-by: bert <bert.timmerman@xs4all.nl>