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