Update protobuf library from 2.3 to 2.6.

Copied in all files from the open source protobuf project at commit
edc5994525c79cd1919859a370837a6ff7c8e308, removing files which have
been renamed (COPYING.txt -> LICENSE, README.txt -> README.md).

Removed 2.3 prebuilts, which is an approach that will not work due to
incompatibility with the 2.6 runtime.

Merged in micro/nano-specific changes in the following files:

-Android.mk - updated list of C++/Java sources, bumped versions
-java/README.txt - merged in micro/nano instructions, bumped versions
-java/pom.xml - merged in micro/nano build rules, set packaging to jar
-src/Makefile.am - merged in references to micro/nano generators
-src/google/protobuf/compiler/javamicro/javamicro_file.h - imported
 google/protobuf/compiler/code_generator.h and removed redundant
 OutputDirectory class.
-src/google/protobuf/compiler/javanano/javanano_file.h - same
-Replaced instances of vector with std::vector as needed to get
 libprotobuf-cpp-full to compile. Plan to upstream this fix per
 discussion with protobuf maintainers.

Reran autogen.sh to update ./configure and associated scripts.

Change-Id: I949d32fb5126f1c05e2a6ed48f6636a4a9b15a48

1 files changed, 34 insertions, 2 deletions

diff --git a/python/README.txt b/python/README.txt
index 96f1a73..adfa46b 100644
--- a/python/README.txt
+++ b/python/README.txt
@@ -43,9 +43,13 @@ Installation
 
      $ protoc --version
 
-4) Run the tests:
+4) Build and run the tests:
 
-     $ python setup.py test
+     $ python setup.py build
+     $ python setup.py google_test
+
+     If you want to test c++ implementation, run:
+     $ python setup.py test --cpp_implementation
 
    If some tests fail, this library may not work correctly on your
    system.  Continue at your own risk.
@@ -61,8 +65,13 @@ Installation
 5) Install:
 
      $ python setup.py install
+     or:
+     $ python setup.py install --cpp_implementation
 
    This step may require superuser privileges.
+   NOTE: To use C++ implementation, you need to install C++ protobuf runtime
+   library of the same version and export the environment variable before this
+   step. See the "C++ Implementation" section below for more details.
 
 Usage
 =====
@@ -71,3 +80,26 @@ The complete documentation for Protocol Buffers is available via the
 web at:
 
   http://code.google.com/apis/protocolbuffers/
+
+C++ Implementation
+==================
+
+The C++ implementation for Python messages is built as a Python extension to
+improve the overall protobuf Python performance.
+
+To use the C++ implementation, you need to:
+1) Install the C++ protobuf runtime library, please see instructions in the
+   parent directory.
+2) Export an environment variable:
+
+  $ export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=cpp
+  $ export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION_VERSION=2
+
+You need to export this variable before running setup.py script to build and
+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 test` after setting the
+variable to "cpp", so the tests will be against C++ implemented Python
+messages.
+