Include todo Bash completion from the todo.txt Wiki.

This is f32aba2 of https://github.com/ginatrapani/todo.txt-cli/wiki/Tips-and-Tricks, last edited 30-Oct-2011.

todo_completion

@@ -0,0 +1,33 @@
+_todo()
+{
+    local cur prev opts
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+    COMMANDS="add a addto addm append app archive command del  \
+              rm depri dp do help list ls listall lsa listcon  \
+              lsc listfile lf listpri lsp listproj lsprj move  \
+              mv prepend prep pri p replace report"
+    # Add custom commands from add-ons, if installed.
+    COMMANDS="$COMMANDS $('ls' ${TODO_ACTIONS_DIR:-$HOME/.todo.actions.d}/ 2>/dev/null)"
+    OPTS="-@ -@@ -+ -++ -d -f -h -p -P -PP -a -n -t -v -vv -V -x"
+    if [ "${cur:0:1}" == "+" ]; then
+        completions="$(todo.sh listproj)"
+    elif [ "${cur:0:1}" == "@" ]; then
+        completions="$(todo.sh listcon)"
+    elif [ $COMP_CWORD -eq 1 ]; then
+        completions="$COMMANDS $OPTS"
+    else
+        case "${prev}" in
+            -*) completions="$COMMANDS $OPTS";;
+            *)  return 0;;
+        esac
+    fi
+    COMPREPLY=( $( compgen -W "$completions" -- $cur ))
+    return 0
+}
+complete -F _todo todo.sh
+# If you define an alias (e.g. "t") to todo.sh, you need to explicitly enable
+# completion for it, too:
+complete -F _todo t
+complete -F _todo todo