update package.json, add mocha to devDeps and test script
update package.json, add mocha to devDeps and test script

radio412/suncalc,Art/suncalc,vxvinh1511/suncalc,mourner/suncalc,OSMBuildings/suncalc,jck000/suncalc,randomite/suncalc,AlekseyMartynov/suncalc