Merge branch 'master' into prop_types

# Conflicts:
#	CHANGELOG.md

Author: pmajkutewicz

CHANGELOG.md

@@ -1,4 +1,5 @@
 # 1.0.1 Release
+- Fix bug in componentWillUnmount->safeRemoveLayer where getPanes doesn't return anything so .contains is called on undefined. 
 - Fixed warning "Accessing PropTypes via the main React package is deprecated"
 
 # 1.0.0 Release

lib/HeatmapLayer.js

@@ -68,7 +68,7 @@ function safeRemoveLayer(leafletMap, el) {
   var _leafletMap$getPanes = leafletMap.getPanes(),
       overlayPane = _leafletMap$getPanes.overlayPane;
 
-  if (overlayPane.contains(el)) {
+  if (overlayPane && overlayPane.contains(el)) {
     overlayPane.removeChild(el);
   }
 }

src/HeatmapLayer.js

@@ -65,7 +65,7 @@ function isInvalidLatLngArray(arr: Array<number>): boolean {
 
 function safeRemoveLayer(leafletMap: Map, el): void {
   const { overlayPane } = leafletMap.getPanes();
-  if (overlayPane.contains(el)) {
+  if (overlayPane && overlayPane.contains(el)) {
     overlayPane.removeChild(el);
   }
 }