Using the cleaninput function, to escape &'s on certain actions.
Currently the actions needing escaped &'s are append, prepend and replace.
Other actions including add need unescaped &'s.
Add a test_todo_session function to test-lib.sh that enables
easy recording of input and output from todo.sh (including
annotation of exit status for testing error cases).
Begin to port and re-factor testsuite.txt into smaller
test cases, starting with basic add list functionality
and replace functionality.
Thanks to Philippe Teuwen <phil@teuwen.org> for feedback
and improvements.
Signed-off-by: Emil Sit <sit@emilsit.net>
