settings: Add option to toggle Error Reporting.

Adds an option to enable or disable sentry error
reporting under Advanced section in General Settings. 
Handles both main and renderer processes.

Also, changes the domain used to resolve proxy
in proxy-util from google.com to example.com.

Fixes #702.

app/renderer/js/utils/proxy-util.js

@@ -52,7 +52,7 @@ class ProxyUtil {
 	resolveSystemProxy(mainWindow) {
 		const page = mainWindow.webContents;
 		const ses = page.session;
-		const resolveProxyUrl = 'www.google.com';
+		const resolveProxyUrl = 'www.example.com';
 
 		// Check HTTP Proxy
 		const httpProxy = new Promise(resolve => {