More tolerant parsing of lat/lon

[nerik]

Kartograph breaks when entering lat/lon pairs with commas instead of points as decimal separators.

I have a csv file generated by Tableau which have commas in lat/lon pairs, so it maybe something happening quite often.

I'd gladly make a PR but I don't know Coffee :/

Simple fix in js :
function LonLat(lon, lat, alt) {
if (alt == null) {
alt = 0;
}
if (lon.replace !== undefined) lon = lon.replace(',','.');
if (lat.replace !== undefined) lat = lat.replace(',','.');
if (alt.replace !== undefined) alt = alt.replace(',','.');