[ts] Fixed curve parsing in SkeletonJson. Closes #1537.

spine-ts/build/spine-all.js

@@ -6147,7 +6147,7 @@ var spine;
 			skeletonData.animations.push(new spine.Animation(name, timelines, duration));
 		};
 		SkeletonJson.prototype.readCurve = function (map, timeline, frameIndex) {
-			if (!map.curve)
+			if (!map.hasOwnProperty("curve"))
 				return;
 			if (map.curve == "stepped")
 				timeline.setStepped(frameIndex);

spine-ts/build/spine-canvas.js

@@ -6147,7 +6147,7 @@ var spine;
 			skeletonData.animations.push(new spine.Animation(name, timelines, duration));
 		};
 		SkeletonJson.prototype.readCurve = function (map, timeline, frameIndex) {
-			if (!map.curve)
+			if (!map.hasOwnProperty("curve"))
 				return;
 			if (map.curve == "stepped")
 				timeline.setStepped(frameIndex);

spine-ts/build/spine-core.js

@@ -6147,7 +6147,7 @@ var spine;
 			skeletonData.animations.push(new spine.Animation(name, timelines, duration));
 		};
 		SkeletonJson.prototype.readCurve = function (map, timeline, frameIndex) {
-			if (!map.curve)
+			if (!map.hasOwnProperty("curve"))
 				return;
 			if (map.curve == "stepped")
 				timeline.setStepped(frameIndex);

spine-ts/build/spine-player.js

@@ -6147,7 +6147,7 @@ var spine;
 			skeletonData.animations.push(new spine.Animation(name, timelines, duration));
 		};
 		SkeletonJson.prototype.readCurve = function (map, timeline, frameIndex) {
-			if (!map.curve)
+			if (!map.hasOwnProperty("curve"))
 				return;
 			if (map.curve == "stepped")
 				timeline.setStepped(frameIndex);

spine-ts/build/spine-threejs.js

@@ -6147,7 +6147,7 @@ var spine;
 			skeletonData.animations.push(new spine.Animation(name, timelines, duration));
 		};
 		SkeletonJson.prototype.readCurve = function (map, timeline, frameIndex) {
-			if (!map.curve)
+			if (!map.hasOwnProperty("curve"))
 				return;
 			if (map.curve == "stepped")
 				timeline.setStepped(frameIndex);

spine-ts/build/spine-webgl.js

@@ -6147,7 +6147,7 @@ var spine;
 			skeletonData.animations.push(new spine.Animation(name, timelines, duration));
 		};
 		SkeletonJson.prototype.readCurve = function (map, timeline, frameIndex) {
-			if (!map.curve)
+			if (!map.hasOwnProperty("curve"))
 				return;
 			if (map.curve == "stepped")
 				timeline.setStepped(frameIndex);

spine-ts/core/src/SkeletonJson.ts

@@ -784,7 +784,7 @@ module spine {
 		}
 
 		readCurve (map: any, timeline: CurveTimeline, frameIndex: number) {
-			if (!map.curve) return;
+			if (!map.hasOwnProperty("curve")) return;
 			if (map.curve == "stepped")
 				timeline.setStepped(frameIndex);
 			else {