#38 User unfriendly keyboard behavior

[Marc-Antoine Ruel]

I think having a different "merge cursor" and "text
cursor" is a bad idea. At least, there should be way to
disable this behavior.

The current ways to move the "merge cursor": right
mouse click, Ctrl-PageUp / PageDown and Ctrl-Arrows,
are pretty user unfriendly.

I think the text cursor and the current merge line should
be the same so it is easier to use because the "two
cursors" concept is pretty unusual. Just don't show the
brown background when there is no difference block at
the current text cursor line.

Enough ranting :) here's the real bug: the Ctrl-
PageUp/PageDown defaults to PageUp/PageDown
when there is no conflicts left in the corresponding
direction which is confusing for the user: is there a
remaining conflict or not?