Refactor and fix multiple max_until recusion (#10)

* wip refactor engine

* wip 2 refactor engine

* wip 3 refactor engine

* wip 3 refactor engine

* wip 4 refactor engine

* wip 5 refactor engine

* refactor seperate Stacks

* fix clippy

* fix pymatch and search restore _stacks

* fix toplevel

* fix marks panic

* fix double max_until repeat context

* clearup

* update version to 0.2.0

Author: qingshi163

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "sre-engine"
-version = "0.1.2"
+version = "0.2.0"
 authors = ["Kangzhi Shi <shikangzhi@gmail.com>", "RustPython Team"]
 description = "A low-level implementation of Python's SRE regex engine"
 repository = "https://github.com/RustPython/sre-engine"