merge tags/2.6.0 into trunk

python/README.txt

diff --git a/python/README.txt b/python/README.txt
index 4ed9bc0..9ba42f8 100644
--- a/python/README.txt
+++ b/python/README.txt
@@ -47,9 +47,9 @@
 
      $ python setup.py build
      $ python setup.py google_test
-     
+
      if you want to test c++ implementation, run:
-     $ python setup.py google_test --cpp_implementation
+     $ python setup.py test
 
    If some tests fail, this library may not work correctly on your
    system.  Continue at your own risk.
@@ -66,7 +66,7 @@
 
      $ python setup.py install
      or:
-     $ python setup.py install --cpp_implementation
+     $ python setup.py install --nocpp_implementation
 
    This step may require superuser privileges.
    NOTE: To use C++ implementation, you need to install C++ protobuf runtime
@@ -101,8 +101,7 @@
 install the extension.  You must also set the variable at runtime, otherwise
 the pure-Python implementation will be used. In a future release, we will
 change the default so that C++ implementation is used whenever it is available.
-It is strongly recommended to run `python setup.py google_test
---cpp_implementation` after setting the
+It is strongly recommended to run `python setup.py test` after setting the
 variable to "cpp", so the tests will be against C++ implemented Python
 messages.