Update electron version to 2.0.8 to address segmentation fault

See #124

Author: jonmmease

README.md

@@ -31,7 +31,7 @@ If you have Node.js installed (recommended v8.x), you can easily install Orca
 using npm as:
 
 ```
-$ npm install -g electron@1.8.4 orca
+$ npm install -g electron@2.0.8 orca
 ```
 
 which makes the `orca` executable available in your path.

package-lock.json

@@ -82,7 +82,7 @@
   "devDependencies": {
     "cross-env": "^5.1.4",
     "devtron": "^1.4.0",
-    "electron": "^1.8.4",
+    "electron": "^2.0.8",
     "electron-builder": "^20.9.2",
     "electron-debug": "^1.4.0",
     "image-size": "^0.6.3",