Fix problem with checking versions of plugins carrying a badly formatted "version" field

boot/boot.js

@@ -357,8 +357,13 @@ $tw.utils.parseVersion = function(version) {
 Returns true if the version string A is greater than the version string B
 */
 $tw.utils.checkVersions = function(versionStringA,versionStringB) {
-	var versionA = $tw.utils.parseVersion(versionStringA),
-		versionB = $tw.utils.parseVersion(versionStringB),
+	var defaultVersion = {
+			major: 0,
+			minor: 0,
+			patch: 0
+		},
+		versionA = $tw.utils.parseVersion(versionStringA) || defaultVersion,
+		versionB = $tw.utils.parseVersion(versionStringB) || defaultVersion,
 		diff = [
 			versionA.major - versionB.major,
 			versionA.minor - versionB.minor,