- Add in/outbound group unit test OK

...sdk/src/androidTest/java/org/matrix/olm/OlmGroupTest.java

...dk/olm-sdk/src/main/java/org/matrix/olm/OlmException.java

.../src/main/java/org/matrix/olm/OlmInboundGroupSession.java

...src/main/java/org/matrix/olm/OlmOutboundGroupSession.java

...LibSdk/olm-sdk/src/main/jni/olm_inbound_group_session.cpp

...ibSdk/olm-sdk/src/main/jni/olm_outbound_group_session.cpp

java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_session.cpp

java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_utility.cpp

java/android/OlmLibSdk/olm-sdk/src/main/jni/olm_utility.h