download apk, request permission and install app update

app/src/fatweb/AndroidManifest.xml

...ap.bitmaskclient/appUpdate/DownloadBroadcastReceiver.java

...va/se.leap.bitmaskclient/appUpdate/DownloadConnector.java

....bitmaskclient/appUpdate/DownloadNotificationManager.java

...java/se.leap.bitmaskclient/appUpdate/InstallActivity.java

app/src/main/java/se/leap/bitmaskclient/Constants.java

app/src/main/java/se/leap/bitmaskclient/StartActivity.java

...in/java/se/leap/bitmaskclient/utils/PreferenceHelper.java

app/src/main/res/values/strings.xml