Check if Android exposes servicechanged; if not, consider exposing re-discover function

[jyasskin]

No description provided.

[beaufortfrancois]

According to https://devzone.nordicsemi.com/question/22751/nrftoobox-on-android-not-recognizing-changes-in-application-type-running-on-nordic-pcb/:

a) when not bonded - android should never cache services if such characteristic is present in Generic Attribute service. However it always does - this is the Android bug, reported here: https://code.google.com/p/android/issues/detail?id=81130

b) when bonded - a device may enable CCCD indications on Service Changed char. Whenever Android receives this indication it will perform service rediscovery automatically. When writing Android code make sure that you give ~2 sec after you get onConnectionStateChange(Connected) event before calling gatt.discoverServices() when you expect that the indication may be received. If you call it immediately, inside the onConnStateCh callback, you'll get old services as this callback is called immediately when you connect but before the bond has been re-established and the indication was sent.