tableprinter: first shot on update of internals

tableprinter: first shot on update of internals

 - due to changes in the internals appends are no longer support
 - each column type now supports multiple copies in the output with
   potentially different output format. However, some column types
   are kept separated: uint vs. hex (historical reasons).
 - when the API user starts using table_col_printf or
   table_col_fbstart then the different kind of formats are ignored.