Add two network related permissions to AndroidManifest.xml

XWalk Core library will auto detect network status, and below two permissions are needed:
  android.permission.ACCESS_NETWORK_STATE
  android.permission.ACCESS_WIFI_STATE
Add these two permissions to AndroidManifest.xml

BUG=XWALK-1480
Merge pull request #106 from kurli/detect-network

Add two network related permissions to AndroidManifest.xml