* fcl-db: dbase: 
- Visual Foxpro support for reading/writing backlink (to .dbc database container file)
- No support yet for the .dbc format itself, e.g. larger field/table names and referential integrity
- Renamed header parts to properly reflect status (i.e. at end of header rather than after header)
- Updated comments
- code layout



git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@28017 3ad0048d-3df7-0310-abae-a5850022a9f2