Fixes #927, update uglify and esprima

Author: jrburke

build/jslib/esprima.js

@@ -1325,6 +1325,7 @@
         try {
             return new RegExp(pattern, flags);
         } catch (exception) {
+            /* istanbul ignore next */
             return null;
         }
     }
@@ -1521,7 +1522,7 @@
             return value && (value.length > 1) && (value[0] >= 'a') && (value[0] <= 'z');
         }
 
-        previous = extra.tokenValues[extra.tokens.length - 1];
+        previous = extra.tokenValues[extra.tokenValues.length - 1];
         regex = (previous !== null);
 
         switch (previous) {
@@ -5707,7 +5708,7 @@
     }
 
     // Sync with *.json manifests.
-    exports.version = '2.7.2';
+    exports.version = '2.7.3';
 
     exports.tokenize = tokenize;