Added a todo.txt plugin that reintroduces functionality they removed, stopgap presently.

todo.actions.d/done.sh

@@ -0,0 +1,17 @@
+#!/bin/bash
+
+action=$1
+shift
+
+[ "$action" = "usage" ] && {
+  echo "  done:"
+  echo "    done \"THING THAT WAS ALREADY COMPLETED\""
+  echo "      add an item and mark it as done in one step"
+  echo ""
+  exit
+}
+
+if "$TODO_SH" command add "$@"; then
+  line=`wc -l "$TODO_FILE" | cut -d' ' -f1`
+  "$TODO_SH" command do "$line"
+fi