Merge branch 'master' into dev

examples/webgl_custom_attributes_particles3.html

@@ -270,7 +270,7 @@
 			for( var i = 0; i < attributes.size.value.length; i ++ ) {
 
 				if ( i < vc1 )
-					attributes.size.value[ i ] = 26 + 32 * Math.sin( 0.1 * i + 0.6 * time );
+					attributes.size.value[ i ] = Math.max(0, 26 + 32 * Math.sin( 0.1 * i + 0.6 * time ));
 
 
 			}