Call MakeVisible() to "scroll" the requested area into view if necessary

Change-Id: I72673d0529261239600eaf9f480f62c3d3dc85fd
Do use scaling after all

It is needed because we want to be able to render different zoom
levels of tiles of course.

But invert the scale from how it was previously. Increasing what is
here called "tile size" (i.e. the size in document coordinates of the
rectangle to be rendered) should mean the rendered text gets smaller,
not larger. Also, use the same units (twips) in numerator and
denominator.

Change-Id: I461f887461247777af1a9402de112d42c8423293
Adjust parameter defaults to give pleasant result

Change-Id: Ifee900344547ef25b2041d25c13fcbc50428485e