Get rid of a couple of copies of the CC0 text. Add header comment to
CC0 files to remind people editing them what the terms are. Also add
some missing XML headers. The header comments in layouts won't bloat
the binary - they get stripped out before compressing, same as any other
comments.
-----------------------------------
nimbus: BBC BASIC V1.00a, RM Nimbus General Utility Disk, IBM Mode Software for Nimbus PC Rel.3, IBM Mode Software For Nimbus PC V2.61,
Microsoft Windows ISV Toolkit Release 1.02, Nimbus Winchester Format Tools, Parallel Printer Driver Parallel Board For I/O Board Version V1.0G,
RM BASIC V1.0F, RM LOGO V1.0D, Release Disk SetPC V2.90 IBM Mode, RM Nimbus Sketchpad Driver V1.0B, Steed Ver 1.4A
RM Nimbus PC Upgrade Disk DOS 3.1 Rel 3.10.A, Microsoft Windows Release 1.02 Stand Alone, Microsoft Windows Release 1.03 Stand Alone
Microsoft Windows 2.03 for Nimbus PC System, Microsoft Windows V2.1 Presentation Manager for Nimbus PC186, Microsoft Windows 3 Standalone PC 186
WordStar Rel. 3.30, XferCPM V1.0A
