adding Function support
adding support for aggregated attributes
improved selector and selector parser to support groupy
adding clone method to Executors
adding attributeAggregators
adding AttributeProcessor and AttributeExecutors
support parsing of groupby aggregated attributes
modified PartitionStreamreceiver
adding comments
adding DefinitionNotExist Exception
enhancing exception message
removing validator exception
removing validator classes and moving validation logic into parsers.
merge remote tracking branch sacjaya/Siddhi-3.0.0
merge remote tracking branch sacjaya/Siddhi-3.0.0
test cases
adding testcases
adding equalsIgnoreAnnotation method
using equalsIgnoreAnnotation method instead of equals method to compare streamDefinitions
aggregated attributes - supporting expired events