Update vendor/underscore to v1.5.1 and update copyrights and tested environments.

Former-commit-id: 3bdfb1de97d08d05199f5f97c9c3145d7068e7fd

build/minify.js

@@ -502,7 +502,7 @@
       // restrict lines to 500 characters for consistency with the Closure Compiler
       var stream = uglifyJS.OutputStream({
         'ascii_only': !this.isTemplate,
-        'comments': /@cc_on|@license|@preserve/i,
+        'comments': /^!|@cc_on|@license|@preserve/i,
         'max_line_len': 500,
       });
 

build/post-compile.js

@@ -10,8 +10,7 @@
   var licenseTemplate = [
     '/**',
     ' * @license',
-    ' * Lo-Dash <%= VERSION %> lodash.com/license',
-    ' * Underscore.js 1.4.4 underscorejs.org/LICENSE',
+    ' * Lo-Dash <%= VERSION %> lodash.com/license | Underscore.js 1.5.1 underscorejs.org/LICENSE',
     ' */'
   ].join('\n');