- add an internal specific JNI function (javaCStringToUtf8()) to perform the UTF-8 conversion
- the SDK is configured to enable/disable the use of javaCStringToUtf8()

- return code is a basic error code (0 OK, -1  KO)
Remove TODO comments

- New class CommonSerializeUtils: helper class dedicated to serialization, to contain common code to all the OlmXXX classes that require to be serialized
- make OlmXXX classes extending CommonSerializeUtils

- OlmException class extends now from IOException
- update corresponding serializing unit tests
 - update

Add new tests for multiple creations of account and outbound group sessions: check random generation function in JNI works properly

Rename local parameter properly

- previously the random seed was seconds based, and it could originate identical identity keys for different OlmAccount

- add a buildJavaDoc task in build.gradle
- update classes javadoc headers

- add logs in verifyEd25519SignatureJni() to print the key used

Add sanity tests for OlmAccount and OlmSession
Add a first version of MatchInboundSession