Bugfix, added xmlns tag to svg map

Should be there for everything to work correctly
Added calc of area, centroid and bbox for map obj

Now the area and centroid is calculated for each area of each country.
Then a bounding box is defined as the bounding box around the largest
area. I also determine -- for each area -- if it may be in need of special
highlighting to easier spot it. The calculation takes a bit of time but is
acceptable.
Bugfix, zooming works better

I had previously not set the width of the zoom boxes. This could cause
some parts of the area to be not visible. I have now calculated good width
values for the areas so that the entire area is always visible.
Added zoom out with click/dblclick on water

click will zoom out a bit, double click will zoom out entirely.
Animated zoom and possibility to country zoom

Zooming on the map is now animated through svg animation of the viewBox.
The set_zoom function also accepts a country code as argument and will
then zoom in to the boundign box of that country. That functionality is
however not implemented in the rest of the code yet.
Added set_prop_class

Added a function to set/unset the class of a prop. This function will also
call an external function if defined, so that I can trigger events on
class change, e.g. highlight a country with an animation.
Added flashy animations/highlights/events

The state of this will probably change. I have added flashing circles to
show small countries, the map list scrolls automatically. It is possible
to zoom in on countries by clicking on map or flag.