Arch Linux support

Work-in-progress:
- /etc/conf.d/dnscrypt-proxy file for each provider
- PKGBUILD for AUR
- Test cases: missing libsodium, not installed, installed
Update dnscrypt-autoinstall-aur
Update and rename dnscrypt-autoinstall-aur to dnscrypt-autoinstall-aur.sh
formatting
Create dnscrypt-proxy-opendns
function remove, chattr +i resolv.conf
Prevent overwrite of resolv.conf
Merge pull request #1 from AladW/patch-4

Patch 4
Update dnscrypt-autoinstall.sh
Create PKGBUILD
Create dnscrypt-autoinstall.install
Arch folder
Update PKGBUILD
Update and rename dnscrypt-autoinstall-aur.sh to dnscrypt-autoinstall.sh
post_install
move to .install (post_install)
Update dnscrypt-autoinstall.sh
Update dnscrypt-autoinstall.install
Update dnscrypt-autoinstall.sh
Update PKGBUILD