v0.5.0

Changelog

• b6f3ad6 add more join benchmark
• 54575a2 cache single value store
• 18f9d7f closure api with less storage
• 3cf74c7 fix ordering of marshaled tuple
• 4ffa564 new closure and merge join
• dbdd087 refactor closure wip
• 1903fc5 refactor datalog query to become closure
• f34d8b1 refactor join code to make it cleaner and faster
• ee149c2 refactored index, where, join conditions
• fe51555 refactored joinedquerynode propagatetoparents
• 2ee046f update documentations and tests to use newer api
• 8396795 update readme to reflect refactor
• 64d9472 use newer api and undo merge sort implementation