- remove compiler warnings when logs are not enabled
- new getInstanceId() function to refactor code

- new JNI API: serializeDataWithKeyJni() and initWithSerializedDataJni()
- update account unit test
- modify OlmAccount constructor API: an exception may be thrown

Fix verifyEd25519Signature() API to properly return the error message in case signature verification failed
- update unit tests

- add unit tests for OlmUtility
- rename OlmGroupTest to OlmGroupSessionTest
- update OlmException

- Introducing namespace AndroidOlmSdk
- Fix logs (function names mixed up)
- Add new check based on the calling java object instance type (IsInstanceOf())
- Fix return value for getXXXInstanceId() in case of failure. Now 0 is returned.

- change return code from removeOneTimeKeysForSession() (direct value from JNI is now returned)

- Modify constructors for inbound and outbound group sessions
- Add new Ecxception class

- Fix warning compiler

- Simplify JNI function signatures definition (Account & Session)

- review comments header
- refactor utility functions

 - new file olm_utility.cpp to have a stand alone function to initialize/alloc a random buffer
 - new class OlmMessage
 - complete OlmSession API with encryptMessage()
 - comments review
 - OlmAccount unit tests are green
 - new gradle to compile the shared lib according to debug mode