Remove os_msdos.txt due to dropped MS-DOS support
Runtime: Support Arch Linux/Pacman file types.
Merge pull request #1082 from fornwall/remove-os-msdos-txt

Remove os_msdos.txt due to dropped MS-DOS support
Merge pull request #1087 from fwalch/archlinux-filetypes

Runtime: Support Arch Linux/Pacman file types.
Remove version{4,5,6,7}.txt
Update CONTRIBUTING.md and README.md #740

- recommend task/subtask convention for commit messages
Merge pull request #1116 from fornwall/remove-versions-txt

Remove version{4,5,6,7}.txt