ADD: scripts from other branch

scripts/nr

···
+#!/usr/bin/env rc
+
+flag e +
+flag x +
+
+exec nix run 'nixpkgs#'^$*

scripts/update-src

···
+#!/usr/bin/env rc
+
+background=()
+for(repo in `{cat downstream}) {
+    echo Updating $repo
+    git -C $repo fetch --all --tags --prune --force &
+    background=($apid $background)
+}
+
+for (i in $background) {
+    wait $i
+}
+
+echo Done!