* deprecate py.magic.invoke/revoke in favour of

the new py.code.patch_builtins, py.code.unpatch_builtins

* deprecate py.magic.patch/revert

* deprecate py.magic.AssertionError in favour of py.code._AssertionError

* introduced pytest_assertion plugin.

--HG--
branch : trunk

py/code/oldmagic2.py

@@ -0,0 +1,6 @@
+
+import py
+
+py.log._apiwarn("1.1", "py.magic.AssertionError is deprecated, use py.code._AssertionError", stacklevel=2)
+
+from py.code import _AssertionError as AssertionError