title: XCGLogger 3.0 doesn't write logfile to filesystem (iOS 9)
body: <p>I want to use XCGLogger 3.0 to do the logging in an iOS9 app written in Swift 2. In the AppDelegate, I define</p>
  <pre><code>let log = XCGLogger.defaultInstance() 
  </code></pre>
  <p>and in application:didFinishLaunchingWithOptions I do the setup with:</p>
  <pre><code>log.setup(.Debug, showThreadName: true, showLogLevel: true, showFileNames: true, showLineNumbers: true, writeToFile: &quot;/tmp/app.log&quot;, fileLogLevel: .Debug)
  </code></pre>
  <p>When I start the app in the simulator I see the output of XCGLogger in the console of XCode 7. The output is:</p>
  <blockquote>
  <p>2015-11-04 18:28:40.798 [Info] &gt; myapp Version: 1.0 Build: 1 PID: 49243</p>
  <p>2015-11-04 18:28:40.798 [Info] &gt; XCGLogger Version: 3.0 - LogLevel: Debug</p>
  <p>2015-11-04 18:28:40.801 [Info] &gt; XCGLogger writing to log to: file:///tmp/app.log</p>
  </blockquote>
  <p>But when I look at the sandbox filesystem of the correct simulator instance (using SimPholders2), there is no logfile app.log.</p>
  <p>It's even worse when I start the app on my IPhone 6. The output in the XCode console is:</p>
  <blockquote>
  <p>2015-11-04 18:36:14.692 [Error] &gt; Attempt to open log file for writing failed: The operation couldn’t be completed. (Cocoa error 2.)</p>
  </blockquote>
  <p>I also tried different pathes like &quot;/tmp/app.log&quot;, &quot;Library/Caches/de.myidentifier.myapp/app.log&quot;, &quot;/Library/Caches/de.myidentifier.myapp/app.log&quot; etc. but without success...</p>
  <p>What am I doing wrong?</p>