adding SiddhiManager and ExecutionPlanRuntime
changes related to public jira https://wso2.org/jira/browse/CEP-944
changes related to public jira https://wso2.org/jira/browse/CEP-940
changes related to public jira https://wso2.org/jira/browse/CEP-941
changes related to public jira https://wso2.org/jira/browse/CEP-942
Merge pull request #12 from sacjaya/Siddhi-3.0.0

Siddhi 3.0.0 - siddhi core implementation