Exporting a World-Map

This patch adds the world map exporter.

- add worldmap-save.c that writes the html to the file
- use Google maps v3 API to put the place marks on the map
- add worldmap-options.h to contain some settings for the JS which will
  make it easier for those to be changed
- add save HTML action in the mainwindow user interface

Signed-off-by: Gehad elrobey <gehadelrobey@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Get rid of division by 0 by reshuffling EAD and EAN logic

Signed-off-by: Robert C. Helling <helling@atdotde.de>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>