Make Python rules in Bazel actually work.
In particular: add a BazelPythonSemantics implementation and the respective RuleConfiguredTarget factories, rule class definitions and hook them up with BazelRuleClassProvider. Add implicit dependencies (2to3 is just a stub script for now that always fails) and a tiny exampe.
--
MOS_MIGRATED_REVID=89691827
diff --git a/examples/py_native/bin.py b/examples/py_native/bin.py
new file mode 100644
index 0000000..f79379a
--- /dev/null
+++ b/examples/py_native/bin.py
@@ -0,0 +1,4 @@
+"""A tiny example binary for the native Python rules of Bazel."""
+from examples.py_native.lib import GetNumber
+
+print "The number is %d" % GetNumber()
