title: Cordova/android compile error with crosswalk
body: <p>I have an android/cordova project that uses crosswalk. When I try to build, I have the following error:</p>
  
  <pre><code>:processArmv7DebugManifest/app/platforms/android/AndroidManifest.xml:31:5-74 Error:
      uses-sdk:minSdkVersion 15 cannot be smaller than version 16 declared in library [org.xwalk:xwalk_core_library:20.50.533.12] /app/platforms/android/build/intermediates/exploded-aar/org.xwalk/xwalk_core_library/20.50.533.12/AndroidManifest.xml
      Suggestion: use tools:overrideLibrary="org.xwalk.core" to force usage
  
  
  See http://g.co/androidstudio/manifest-merger for more information about the manifest merger.
  
  :processArmv7DebugManifest FAILED
  
  FAILURE: Build failed with an exception.
  
  * What went wrong:
  Execution failed for task ':processArmv7DebugManifest'.
  &gt; Manifest merger failed : uses-sdk:minSdkVersion 15 cannot be smaller than version 16 declared in library [org.xwalk:xwalk_core_library:20.50.533.12] /app/platforms/android/build/intermediates/exploded-aar/org.xwalk/xwalk_core_library/20.50.533.12/AndroidManifest.xml
      Suggestion: use tools:overrideLibrary="org.xwalk.core" to force usage
  
  * Try:
  Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.
  
  BUILD FAILED
  </code></pre>
  
  <p>But i have ver17 set in my config.xml:</p>
  
  <pre><code>   &lt;preference name="android-minSdkVersion" value="17" /&gt;
      &lt;preference name="android-targetSdkVersion" value="17" /&gt;
  </code></pre>
  
  <p>Furthermore, it is the same in the platforms/android/AndroidManifest.xml:</p>
  
  <pre><code>&lt;uses-sdk android:minSdkVersion="17" android:targetSdkVersion="17" /&gt;
  </code></pre>
  
  <p>I tried to remove and then add back again the crosswalk and "platform android" itself, but error still persists.</p>
  
  <p>Please help</p>