Defining Tasks: Specification

task-sep-char	->	character
Specifies the character used to separate one part of a task name from another.
task-name	->	string
Returns the name of a task.
task-client	->	string
Returns the client of a task.
task-value	->	t
Returns the value of a task, any Lisp object.
(create-task task-name &key (client nil) (value nil))	->	task
Creates a task with the given name, client and value.
(find-task task-name)	->	task
Finds a task by name.
(print-task task &key (stream t))	->	task
Prints out a task's name, client and value (the last using `format`'s `~S` directive).
(print-all-tasks &key (stream t))	->	task
Prints details for all tasks.