16 pacific timezones

Pacific/Apia
Pacific/Auckland
Pacific/Bougainville
Pacific/Chatham
Pacific/Chuuk
Pacific/Easter
Pacific/Efate
Pacific/Enderbury
Pacific/Fakaofo
Pacific/Fiji
Pacific/Funafuti
Pacific/Galapagos
Pacific/Gambier
Pacific/Guadalcanal
Pacific/Guam
Pacific/Honolulu

Also:
- adding option to intersect with multipolygon
- correcting OSM identifier for USA

Refs #1
diff --git a/index.js b/index.js
index 36d424e..e76708a 100644
--- a/index.js
+++ b/index.js
@@ -3,6 +3,7 @@
 
 var async = require('async'),
   jsts = require('jsts'),
+  multiPolygon = require('turf-multipolygon'),
   overpass = require('query-overpass'),
   polygon = require('turf-polygon'),
   shp = require('shpjs')
@@ -164,6 +165,8 @@
     geoJson = require('./downloads/' + source.id + '.json')
   } else if(source.source === 'manual-polygon') {
     geoJson = polygon(source.data).geometry
+  } else if(source.source === 'manual-multipolygon') {
+    geoJson = multiPolygon(source.data).geometry
   } else {
     var err = new Error('unknown source: ' + source.source)
     throw err