RELEASE NOTES

FIX BUGS:
[TD-1533]: fix the parse jdbc url error
[TD-1523]: fix memory leaks and refactor some functions.
[TD-225]: fix compiler error on windows
[TD-1532]: fix taosdemo case bug

NEW FEATURES:
[TD-1572]: A JdbcTaosdemo is supported now.
[TD-1603]: add new error code at client side
[TD-1651]: add lgtm code analyzer support.
[TD-1313]: implement getColumns method in the TSDBDatabaseMet…

TEST:
[TD-1386]: add test case for retention
[TD-1587]: add python restful example
[TD-1469]: add test case for alter table and insert