task/list - Returns a list of all tasks.
The method has no parameters.
Returns a JSON document of the following format:
[{id: <number> - The ID of one of the tasks.
text: <string> - The text of the task.
deadline_time: <string> - The Unix timestamp of the deadline of the task.
tags: <string> - The space-separated list of tags.
top_priority: <boolean> - Whether the task is marked as top priority.
insert_time: <number> - The Unix timestamp of when the task was created.
update_time: <number> - The Unix timestamp of when the task was last modified.
}...
]No errors expected.