[LogiLogi-list] work over logi versions

This week I also worked with the PositionRanges to get done this task:
U: A history (diff of versions) screen.

I take me some time to get used to the PositionRanges but finally I
think I get them.
I didn't finished the work but I am getting closer.
Wybo, I am going to commit the changes but it's not the final
solution, and I didn't do the update of some files for some days. so
they will be some conflicts.

The idea is to select two versions and get the merge between them with
a distinguishing color for the text that it's only in one version and
another color for the text that is in both versions.

I know it's really alpha but I want to know If you all like the approach.

Bon weekend,

Miguel