identityKeys and oneTimeKeys return Map instead of JSON.

...k/src/androidTest/java/org/matrix/olm/OlmAccountTest.java

...k/src/androidTest/java/org/matrix/olm/OlmSessionTest.java

...k/src/androidTest/java/org/matrix/olm/OlmUtilityTest.java

...m-sdk/src/androidTest/java/org/matrix/olm/TestHelper.java

...bSdk/olm-sdk/src/main/java/org/matrix/olm/OlmAccount.java

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