Improving functional tests and fixing some bugs:

[nbozic-zz]

• be explicite, when enable tracing is false do not log statement even when it is String query (not prepared statement)
• make core modules readme consistent
• add tracing functional test which is checking both types of statements ( prepared and plain String) and compares log output against sent statement
• cover all modules in basic test
• remove system log for Cassandra after test since it is never deleted and it makes tests pass even if last log is wrong

Fixes #213