implement UDF(single-row udf) plugin loading/testing (not auto-loaded)
fix to return Array instance explicitly
fix api bug for unneeded argument
fix api for plugin bundle style
fix sym available for method name
plugin loader first version (buggy)
fix udf loading bug to work well
fix UDF module namings
add aggregate udf supports
fix to add esper-*.jar for aggregation function interfaces
fix bug of variable name
add utility function and java class conversion for tests
fix wrong variable name
fix to call over ruby bridge method
fix func name not to compete predefied #call method