MIF Filter: make an option of creating trans units when HardReturn symbols appear

[Denis Konovalyenko]

If we take a look at the following UI

we can find out that the < like symbols are HardReturns (\n). So, there should appear

Para 1.

2.1 and

2.2

trans units when a corresponding option is in the act.

For more details please refer to the attached document.

[Denis Konovalyenko]

A related pull request #439 was opened.

[Denis Konovalyenko]

The pull request #439 was merged.

[Denis Konovalyenko]

It was revealed that the hard returns were not correctly serialised.

[Denis Konovalyenko]

A follow-up issue #990 was created.

[Denis Konovalyenko]

A related pull request #442 was merged.