Clean up uses of external URLs
Fix for Mantis 1024: Dead-function stripping
Fix for Mantis 1029: Permit processing #ifdefs within an object declaration (from Andrew Plotkin)
Fix for Mantis 1035: Clean up syntax error recovery for Attribute/Property directives (from Andrew Plotkin)
Fix for Mantis 1036: Report error if file ends in the middle of an object definition (from Andrew Plotkin)
Fix for Mantis 1059: Glulx memory map printing
Update version number to 6.33
Replace bzero() with memset()