add FOSS4G conference, GeoForAll and LibreOffice
add FOSS4G conference, GeoForAll and LibreOffice

ncsu-osgeorel/foss-for-geospatial-analysis,ncsu-osgeorel/foss-for-geospatial-analysis,ncsu-osgeorel/foss-for-geospatial-analysis,ncsu-osgeorel/foss-for-geospatial-analysis