update MAC vm from http://www.mirandabanda.org/files/Cog/VM/VM.r2693/
update Windows vm from http://www.mirandabanda.org/files/Cog/VM/VM.r2693/
update Linux vm from http://www.mirandabanda.org/files/Cog/VM/VM.r2693/
Issue #27 install new vm version: VM.r2693 from http://www.mirandabanda.org/files/Cog/VM/VM.r2693/
Merge branch 'master' into issue_27: Issue #27 ... pick up vm.r2693 changes