Add warning about the demo server

Author: Per Liedman

src/L.Routing.OSRMv1.js

@@ -26,14 +26,30 @@
 				steps: true
 			},
 			polylinePrecision: 5,
-			useHints: true
+			useHints: true,
+			suppressDemoServerWarning: false
 		},
 
 		initialize: function(options) {
 			L.Util.setOptions(this, options);
 			this._hints = {
 				locations: {}
 			};
+
+			if (!this.options.suppressDemoServerWarning &&
+				this.options.serviceUrl.indexOf('//router.project-osrm.org') >= 0) {
+				console.warn('You are using OSRM\'s demo server. ' +
+					'Please note that it is **NOT SUITABLE FOR PRODUCTION USE**.\n' +
+					'Refer to the demo server\'s usage policy: ' +
+					'https://github.com/Project-OSRM/osrm-backend/wiki/Api-usage-policy\n\n' +
+					'To change, set the serviceUrl option.\n\n' +
+					'Please do not report issues with this server to neither ' +
+					'Leaflet Routing Machine or OSRM - it\'s for\n' +
+					'demo only, and will sometimes not be available, or work in ' +
+					'unexpected ways.\n\n' +
+					'Please set up your own OSRM server, or use a paid service ' +
+					'provider for production.');
+			}
 		},
 
 		route: function(waypoints, callback, context, options) {