Bugfix with zooming

When zooming out a bit, it was not possible to zoom in again since
g_zoom_cur was not reset.
Bugfix when making map too small

An error would occur if the width of the map was made to be zero or less.
More zoom/highlgiht functionality

The aid box can be pressed to highlight/zoom in on current country. Also
the flag is scrolled to when playing. One can also press on current
country to zoom in on it.
Sometimes show wrong when guessing on subset

If guessing on map or flag.
Bugfix when game mode = subset

When guessing wrong, it would be internal error when game is done.
Updated spelling on capitals

Brasilia is now spelled Brasília and Djakarta is now spelled Jakarta.

I do not spell Pristina with a caron since that is the serbian spelling,
not the swedish spelling.