Refactored various add functionality to one function. Added tests.

- 'add' and 'addm' now 'addto' with $TODO_FILE instead of user supplied file

- 'addto' now shows the capitalized filename in place of 'TODO:'.
  For example, adding to garden.txt produces a output prefixed by 'GARDEN:'
  (Probably the most controversial part of this commit and up for
  discussion. If kept, the 'listfile' output should be made to match.
  Note that this convention would then minimize standard output by
  dropping the file name.)

- All existing add/addm/add-date tests pass. Two new test sequences were
  added to test 'addto' and 'listfile' functionality.

- A space/tab nuissance was cleared up in the tests/README file.

tests/t1030-addto-date.sh

@@ -0,0 +1,71 @@
+#!/bin/sh
+
+test_description='test the date on addto feature
+
+Tests paths by which we might automatically add
+a date to each item.
+'
+. ./test-lib.sh
+
+touch "$HOME/garden.txt"
+
+#
+# Add and list
+#
+test_todo_session 'cmd line first day' <<EOF
+>>> todo.sh -t addto garden.txt notice the daisies
+GARDEN: '2009-02-13 notice the daisies' added on line 1.
+
+>>> todo.sh listfile garden.txt
+1 2009-02-13 notice the daisies
+--
+TODO: 1 of 1 tasks shown from garden.txt
+EOF
+
+test_tick
+
+test_todo_session 'cmd line second day' <<EOF
+>>> todo.sh -t addto garden.txt smell the roses
+GARDEN: '2009-02-14 smell the roses' added on line 2.
+
+>>> todo.sh listfile garden.txt
+1 2009-02-13 notice the daisies
+2 2009-02-14 smell the roses
+--
+TODO: 2 of 2 tasks shown from garden.txt
+EOF
+
+test_tick
+
+test_todo_session 'cmd line third day' <<EOF
+>>> todo.sh -t addto garden.txt mow the lawn
+GARDEN: '2009-02-15 mow the lawn' added on line 3.
+
+>>> todo.sh listfile garden.txt
+1 2009-02-13 notice the daisies
+2 2009-02-14 smell the roses
+3 2009-02-15 mow the lawn
+--
+TODO: 3 of 3 tasks shown from garden.txt
+EOF
+
+# Switch to config file
+echo "export TODOTXT_DATE_ON_ADD=1" >> todo.cfg
+
+# Bump the clock, for good measure.
+test_tick 3600
+
+test_todo_session 'config file third day' <<EOF
+>>> todo.sh addto garden.txt take out the trash
+GARDEN: '2009-02-15 take out the trash' added on line 4.
+
+>>> todo.sh listfile garden.txt
+1 2009-02-13 notice the daisies
+2 2009-02-14 smell the roses
+3 2009-02-15 mow the lawn
+4 2009-02-15 take out the trash
+--
+TODO: 4 of 4 tasks shown from garden.txt
+EOF
+
+test_done