Drop uuid: filter when loading the task

[tbabej]

Loading tasks does not work with 2.4.0 due to the following bug.

https://bug.tasktools.org/browse/TW-1452

The reason is that vimwiki-tasks uses uuid: filter when loading the task, however, that filter is broken in 2.4.0.

However, referencing tasks directly (using the task info) command works with TW 2.2, 2.3 and 2.4 (I did not test older versions), so changing that should be fairly backwards compatible.

[tbabej]

I added additional modifications for writing the tasks.