Update vendor/underscore to v1.5.0.

Former-commit-id: 8f647bccfdd8fe81473ae7d1354056a928b6f28c

vendor/underscore/underscore.js

@@ -1,4 +1,4 @@
-//     Underscore.js 1.4.4
+//     Underscore.js 1.5.0
 //     http://underscorejs.org
 //     (c) 2009-2011 Jeremy Ashkenas, DocumentCloud Inc.
 //     (c) 2011-2013 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
@@ -66,7 +66,7 @@
   }
 
   // Current version.
-  _.VERSION = '1.4.4';
+  _.VERSION = '1.5.0';
 
   // Collection Functions
   // --------------------
@@ -424,6 +424,9 @@
 
   // Internal implementation of a recursive `flatten` function.
   var flatten = function(input, shallow, output) {
+    if (shallow && _.every(input, _.isArray)) {
+      return concat.apply(output, input);
+    }
     each(input, function(value) {
       if (_.isArray(value) || _.isArguments(value)) {
         shallow ? push.apply(output, value) : flatten(value, shallow, output);
@@ -492,7 +495,7 @@
   // Zip together multiple lists into a single array -- elements that share
   // an index go together.
   _.zip = function() {
-    return _.unzip(slice.call(arguments));
+    return _.unzip.apply(_, slice.call(arguments));
   };
 
   // The inverse operation to `_.zip`. If given an array of pairs it
@@ -501,11 +504,11 @@
   // three element array and so on. For example, `_.unzip` given
   // `[['a',1],['b',2],['c',3]]` returns the array
   // [['a','b','c'],[1,2,3]].
-  _.unzip = function(list) {
-    var length = _.max(_.pluck(list, "length").concat(0));
+  _.unzip = function() {
+    var length = _.max(_.pluck(arguments, "length").concat(0));
     var results = new Array(length);
     for (var i = 0; i < length; i++) {
-      results[i] = _.pluck(list, '' + i);
+      results[i] = _.pluck(arguments, '' + i);
     }
     return results;
   };
@@ -649,11 +652,15 @@
   };
 
   // Returns a function, that, when invoked, will only be triggered at most once
-  // during a given window of time.
-  _.throttle = function(func, wait, immediate) {
+  // during a given window of time. Normally, the throttled function will run
+  // as much as it can, without ever going more than once per `wait` duration;
+  // but if you'd like to disable the execution on the leading edge, pass
+  // `{leading: false}`. To disable execution on the trailing edge, ditto.
+  _.throttle = function(func, wait, options) {
     var context, args, result;
     var timeout = null;
     var previous = 0;
+    options || (options = {});
     var later = function() {
       previous = new Date;
       timeout = null;
@@ -661,7 +668,7 @@
     };
     return function() {
       var now = new Date;
-      if (!previous && immediate === false) previous = now;
+      if (!previous && options.leading === false) previous = now;
       var remaining = wait - (now - previous);
       context = this;
       args = arguments;
@@ -670,7 +677,7 @@
         timeout = null;
         previous = now;
         result = func.apply(context, args);
-      } else if (!timeout) {
+      } else if (!timeout && options.trailing !== false) {
         timeout = setTimeout(later, remaining);
       }
       return result;
@@ -737,7 +744,6 @@
 
   // Returns a function that will only be executed after being called N times.
   _.after = function(times, func) {
-    if (times <= 0) return func();
     return function() {
       if (--times < 1) {
         return func.apply(this, arguments);
@@ -891,6 +897,13 @@
       // unique nested structures.
       if (aStack[length] == a) return bStack[length] == b;
     }
+    // Objects with different constructors are not equivalent, but `Object`s
+    // from different frames are.
+    var aCtor = a.constructor, bCtor = b.constructor;
+    if (aCtor !== bCtor && !(_.isFunction(aCtor) && (aCtor instanceof aCtor) &&
+                             _.isFunction(bCtor) && (bCtor instanceof bCtor))) {
+      return false;
+    }
     // Add the first object to the stack of traversed objects.
     aStack.push(a);
     bStack.push(b);
@@ -907,13 +920,6 @@
         }
       }
     } else {
-      // Objects with different constructors are not equivalent, but `Object`s
-      // from different frames are.
-      var aCtor = a.constructor, bCtor = b.constructor;
-      if (aCtor !== bCtor && !(_.isFunction(aCtor) && (aCtor instanceof aCtor) &&
-                               _.isFunction(bCtor) && (bCtor instanceof bCtor))) {
-        return false;
-      }
       // Deep compare objects.
       for (var key in a) {
         if (_.has(a, key)) {