[ts][player] Better error message serialization.

spine-ts/build/spine-all.js

@@ -12129,7 +12129,7 @@ var spine;
 					skeletonData = json.readSkeletonData(jsonText);
 				}
 				catch (e) {
-					this.showError("Error: could not load skeleton .json.<br><br>" + escapeHtml(JSON.stringify(e)));
+					this.showError("Error: could not load skeleton .json.<br><br>" + e.toString());
 					return;
 				}
 			}
@@ -12140,7 +12140,7 @@ var spine;
 					skeletonData = binary.readSkeletonData(binaryData);
 				}
 				catch (e) {
-					this.showError("Error: could not load skeleton .skel.<br><br>" + escapeHtml(JSON.stringify(e)));
+					this.showError("Error: could not load skeleton .skel.<br><br>" + e.toString());
 					return;
 				}
 			}

spine-ts/build/spine-player.js

@@ -11440,7 +11440,7 @@ var spine;
 					skeletonData = json.readSkeletonData(jsonText);
 				}
 				catch (e) {
-					this.showError("Error: could not load skeleton .json.<br><br>" + escapeHtml(JSON.stringify(e)));
+					this.showError("Error: could not load skeleton .json.<br><br>" + e.toString());
 					return;
 				}
 			}
@@ -11451,7 +11451,7 @@ var spine;
 					skeletonData = binary.readSkeletonData(binaryData);
 				}
 				catch (e) {
-					this.showError("Error: could not load skeleton .skel.<br><br>" + escapeHtml(JSON.stringify(e)));
+					this.showError("Error: could not load skeleton .skel.<br><br>" + e.toString());
 					return;
 				}
 			}

spine-ts/player/src/Player.ts

@@ -867,7 +867,7 @@ module spine {
 				try {
 					skeletonData = json.readSkeletonData(jsonText);
 				} catch (e) {
-					this.showError("Error: could not load skeleton .json.<br><br>" + escapeHtml(JSON.stringify(e)));
+					this.showError("Error: could not load skeleton .json.<br><br>" + e.toString());
 					return;
 				}
 			} else {
@@ -876,7 +876,7 @@ module spine {
 				try {
 					skeletonData = binary.readSkeletonData(binaryData);
 				} catch (e) {
-					this.showError("Error: could not load skeleton .skel.<br><br>" + escapeHtml(JSON.stringify(e)));
+					this.showError("Error: could not load skeleton .skel.<br><br>" + e.toString());
 					return;
 				}
 			}