Added stub for sre_compile(2and3) (#1493)

stdlib/2and3/sre_compile.pyi

@@ -0,0 +1,18 @@
+# Source: https://hg.python.org/cpython/file/2.7/Lib/sre_compile.py
+# and https://github.com/python/cpython/blob/master/Lib/sre_compile.py
+
+import sys
+from sre_parse import SubPattern
+from typing import Any, List, Pattern, Tuple, Type, TypeVar, Union
+
+MAXCODE = ...  # type: int
+if sys.version_info < (3, 0):
+    STRING_TYPES: Tuple[Type[str], Type[unicode]]
+    _IsStringType = int
+else:
+    from sre_constants import _NamedIntConstant
+    def dis(code: List[_NamedIntConstant]) -> None: ...
+    _IsStringType = bool
+
+def isstring(obj: Any) -> _IsStringType: ...
+def compile(p: Union[str, bytes, SubPattern], flags: int = ...) -> Pattern: ...