ENH: Better completion for custom add-ons via new listaddons command.

The todo_completion had the problem that it didn't consider the todo.cfg itself for the location of TODO_ACTIONS_DIR, it just tried the default location or a globally exported config value. With the injection of custom configuration now in place, we can actually delegate the listing to todo.sh itself.
The added built-in "listaddons" command is used for that; it may also be helpful for troubleshooting or to find out about available add-ons. (But the help / shorthelp commands offer more information.)

Additionally, completion is now more precise; only executable actions and no subdirs are listed now; this is also covered by the enhanced test.

The last bonus: The custom add-on actions are now only determined when there's actually completion of commands.

.gitignore

@@ -1,6 +1,3 @@
 VERSION-FILE
 tests/test-results
 tests/trash\ directory.*
-done.txt
-report.txt
-todo.txt

tests/test-lib.sh

@@ -264,7 +264,25 @@ test_expect_success () {
 test_expect_output () {
 	test "$#" = 2 ||
 	error "bug in the test script: not 2 parameters to test-expect-output"
-	test_expect_code_and_output 0 "$@"
+	if ! test_skip "$@"
+	then
+		say >&3 "expecting success and output: $2"
+		test_run_ "$2"
+		if [ "$?" = 0 -a "$eval_ret" = 0 ]
+		then
+			cmp_output=$(test_cmp expect output)
+			if [ "$?" = 0 ]
+			then
+				test_ok_ "$1"
+			else
+				test_failure_ "$@" "
+$cmp_output"
+			fi
+		else
+			test_failure_ "$@"
+		fi
+	fi
+	echo >&3 ""
 }
 
 test_expect_code_and_output () {
@@ -272,11 +290,7 @@ test_expect_code_and_output () {
 	error "bug in the test script: not 3 parameters to test-expect-code-and-output"
 	if ! test_skip "$@"
 	then
-		if [ "$1" = 0 ]; then
-			say >&3 "expecting success and output: $3"
-		else
 		say >&3 "expecting exit code $1 and output: $3"
-		fi
 		test_run_ "$3"
 		if [ "$?" = 0 -a "$eval_ret" = "$1" ]
 		then
@@ -552,16 +566,14 @@ test_tick () {
 }
 
 # Generate and run a series of tests based on a transcript.
-# Usage: test_todo_session "description" <<'EOF'
+# Usage: test_todo_session "description" <<EOF
 # >>> command
 # output1
 # output2
-#
 # >>> command
 # === exit status
-# output3 with empty line (must be escaped here)
-# \
-# output5
+# output3
+# output4
 # EOF
 test_todo_session () {
     test "$#" = 1 ||
@@ -570,7 +582,7 @@ test_todo_session () {
     cmd=""
     status=0
     > expect
-    while IFS= read -r line
+    while read -r line
     do
 	case $line in
 	">>> "*)
@@ -594,9 +606,6 @@ test_todo_session () {
 		> expect
 	    fi
 	    ;;
-	\\)
-	    echo "" >> expect
-	    ;;
 	*)
 	    echo "$line" >> expect
 	    ;;

todo_completion

@@ -58,7 +58,7 @@ _todo()
                             # a safety check of the ls action output.
                             local todo=$( \
                                 eval TODOTXT_VERBOSE=0 $_todo_sh '-@ -+ -p -x command ls "^ *${cur} "' | \
-                                sed -e 's/^ *[0-9]\{1,\} //' -e 's/\((.) \)[0-9]\{2,4\}-[0-9]\{2\}-[0-9]\{2\} /\1/' \
+                                sed -e 's/^ *[0-9]\+ //' -e 's/\((.) \)[0-9]\{2,4\}-[0-9]\{2\}-[0-9]\{2\} /\1/' \
                                     -e 's/\([xX] \)\([0-9]\{2,4\}-[0-9]\{2\}-[0-9]\{2\} \)\{1,2\}/\1/' \
                                     -e 's/[[:space:]]*$//' \
                                     -e '1q' \