Backport: Fix Karma sinon-chai version issues

Previously, we were using the karma-sinon-chai package to
provide sinon-chai to karma.  This used an older version of
sinon-chai, and looks to be no longer maintained (it's been
a month since sinon-chai was updated).  A new package,
karma-sinon-chai-latest, is now used.  This package uses the
latest version of sinon-chai and sinon, just like karma-chai
uses the latest version of chai.

(cherry picked from commit c42ea225)

package.json

@@ -28,23 +28,23 @@
   "devDependencies": {
     "ansi": "^0.3.0",
     "casperjs": "^1.1.0-beta3",
-    "chai": "^1.9.1",
-    "commander": "^2.2.0",
-    "karma": "^0.12.16",
+    "chai": "^1.10.0",
+    "commander": "^2.5.0",
+    "karma": "^0.12.25",
     "karma-chai": "^0.1.0",
-    "karma-mocha": "^0.1.4",
-    "karma-mocha-reporter": "^0.2.5",
+    "karma-mocha": "^0.1.9",
+    "karma-mocha-reporter": "^0.3.1",
     "karma-phantomjs-launcher": "^0.1.4",
-    "karma-sauce-launcher": "^0.2.8",
+    "karma-sauce-launcher": "^0.2.10",
     "karma-sinon": "^1.0.3",
-    "karma-sinon-chai": "^0.1.6",
-    "mocha": "^1.20.1",
-    "open": "0.0.5",
-    "phantom": "^0.6.3",
-    "phantomjs": "^1.9.7-9",
-    "sinon": "^1.10.2",
-    "sinon-chai": "^2.5.0",
-    "spooky": "^0.2.4",
-    "temp": "^0.8.0"
+    "karma-sinon-chai-latest": "^0.1.0",
+    "mocha": "^2.0.1",
+    "open": "^0.0.5",
+    "phantom": "^0.7.0",
+    "phantomjs": "^1.9.12",
+    "sinon": "^1.12.1",
+    "sinon-chai": "^2.6.0",
+    "spooky": "^0.2.5",
+    "temp": "^0.8.1"
   }
 }