Bump cornerstone-core to 2.2.7 and cornerstone-tools to 2.4.0

Packages/ohif-cornerstone/package.js

@@ -6,8 +6,8 @@ Package.describe({
 
 Npm.depends({
     hammerjs: '2.0.8',
-    'cornerstone-core': '2.2.4',
-    'cornerstone-tools': '2.3.9',
+    'cornerstone-core': '2.2.7',
+    'cornerstone-tools': '2.4.0',
     'cornerstone-math': '0.1.6',
     'dicom-parser': '1.8.0',
     'cornerstone-wado-image-loader': '2.1.4',