Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/cmake/README.md

 This directory contains *CMake* files that can be used to build protobuf
 with *MSVC* on *Windows*. You can build the project from *Command Prompt*
 and using an *Visual Studio* IDE.
 
 You need to have [CMake](http://www.cmake.org), [Visual Studio](https://www.visualstudio.com)
 and optionally [Git](http://git-scm.com) installed on your computer before proceeding.
 
 Most of the instructions will be given to the *Сommand Prompt*, but the same
 actions can be performed using appropriate GUI tools.
 
@@ skipping 10 matching lines @@
 
     C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\bin\amd64>cd C:\Path\to
     C:\Path\to>
 
 Where *C:\Path\to* is path to your real working directory.
 
 Create a folder where protobuf headers/libraries/binaries will be installed after built:
 
     C:\Path\to>mkdir install
 
-If *cmake* command is not avaliable from *Command Prompt*, add it to system *PATH* variable:
+If *cmake* command is not available from *Command Prompt*, add it to system *PATH* variable:
 
     C:\Path\to>set PATH=%PATH%;C:\Program Files (x86)\CMake\bin
 
-If *git* command is not avaliable from *Command Prompt*, add it to system *PATH* variable:
+If *git* command is not available from *Command Prompt*, add it to system *PATH* variable:
 
     C:\Path\to>set PATH=%PATH%;C:\Program Files\Git\cmd
 
 Good. Now you are ready to continue.
 
 Getting Sources
 ===============
 
 You can get the latest stable source packages from the
 [releases](https://github.com/google/protobuf/releases) page.
@@ skipping 104 matching lines @@
 
   * Open the generated protobuf.sln file in Microsoft Visual Studio.
   * Choose "Debug" or "Release" configuration as desired.
   * From the Build menu, choose "Build Solution".
 
 And wait for the compilation to finish.
 
 Testing
 =======
 
-To run unit-tests:
+To run unit-tests, first you must compile protobuf as described above.
+Then run:
 
      C:\Path\to\protobuf\cmake\build\release>nmake check
 
 or
 
      C:\Path\to\protobuf\cmake\build\debug>nmake check
 
 You can also build project *check* from Visual Studio solution.
 Yes, it may sound strange, but it works.
 
@@ skipping 40 matching lines @@
 
 or
 
      C:\Path\to\protobuf\cmake\build\debug>nmake install
 
 You can also build project *INSTALL* from Visual Studio solution.
 It sounds not so strange and it works.
 
 This will create the following folders under the *install* location:
   * bin - that contains protobuf *protoc.exe* compiler;
-  * inclue - that contains C++ headers and protobuf *.proto files;
+  * include - that contains C++ headers and protobuf *.proto files;
   * lib - that contains linking libraries and *CMake* configuration files for *protobuf* package.
 
 Now you can if needed:
   * Copy the contents of the include directory to wherever you want to put headers.
   * Copy protoc.exe wherever you put build tools (probably somewhere in your PATH).
   * Copy linking libraries libprotobuf[d].lib, libprotobuf-lite[d].lib, and libprotoc[d].lib wherever you put libraries.
 
 To avoid conflicts between the MSVC debug and release runtime libraries, when
 compiling a debug build of your application, you may need to link against a
 debug build of libprotobufd.lib with "d" postfix.  Similarly, release builds should link against
@@ skipping 94 matching lines @@
 its public interfaces.  MSVC does not provide any reasonable way to export
 template classes from a DLL.  However, in practice, it appears that exporting
 templates is not necessary anyway.  Since the complete definition of any
 template is available in the header files, anyone importing the DLL will just
 end up compiling instances of the templates into their own binary.  The
 Protocol Buffer implementation does not rely on static template members being
 unique, so there should be no problem with this, but MSVC prints warning
 nevertheless.  So, we disable it.  Unfortunately, this warning will also be
 produced when compiling code which merely uses protocol buffers, meaning you
 may have to disable it in your code too.