Evas textblock: improve and fix line range rectangles

Evas textblock: improve and fix line range rectangles

The line range rectangles geometries needed a bit of adjusting. I
started out with fixing T2648. In order to fill the gap between the end
of the line and the margins, the geometry of the last line's character
was used. I am not really sure why. Anyway, we have the line geometry,
so I replaced it with that.

Then, it led me to do some alignment checks, and indeed alignment cases
were not treated. For instance, an LTR paragraph could have a line
aligned with a value greater than 0.0. That means that we should fill
the gap from the left of the line, if it was the last line in a
multi-line selection. The inverse case is for RTL.

I think it now works as it should. Will see if the selection logic is
missing some more stuff once I come up with more example cases.

Fixes T2648.

@fix

Change-Id: Ic8285a9ae389e80c09d84558bc0cda749deaa575