Adds batch file to build nuget packages.

Tools/nuget/build.bat

+@echo off
+setlocal
+set D=%~dp0
+set PCBUILD=%D%..\..\PCBuild\
+
+set BUILDX86=
+set BUILDX64=
+set REBUILD=
+set OUTPUT=
+set PACKAGES=
+
+:CheckOpts
+if "%~1" EQU "-h" goto Help
+if "%~1" EQU "-x86" (set BUILDX86=1) && shift && goto CheckOpts
+if "%~1" EQU "-x64" (set BUILDX64=1) && shift && goto CheckOpts
+if "%~1" EQU "-r" (set REBUILD=-r) && shift && goto CheckOpts
+if "%~1" EQU "-o" (set OUTPUT="/p:OutputPath=%~2") && shift && shift && goto CheckOpts
+if "%~1" EQU "--out" (set OUTPUT="/p:OutputPath=%~2") && shift && shift && goto CheckOpts
+if "%~1" EQU "-p" (set PACKAGES=%PACKAGES% %~2) && shift && shift && goto CheckOpts
+
+if not defined BUILDX86 if not defined BUILDX64 (set BUILDX86=1) && (set BUILDX64=1)
+
+call "%D%..\msi\get_externals.bat"
+call "%PCBUILD%env.bat" x86
+
+if defined PACKAGES set PACKAGES="/p:Packages=%PACKAGES%"
+
+if defined BUILDX86 (
+    if defined REBUILD ( call "%PCBUILD%build.bat" -e -r
+    ) else if not exist "%PCBUILD%win32\python.exe" call "%PCBUILD%build.bat" -e
+    if errorlevel 1 goto :eof
+
+    msbuild "%D%make_pkg.proj" /p:Configuration=Release /p:Platform=x86 %OUTPUT% %PACKAGES%
+    if errorlevel 1 goto :eof
+)
+
+if defined BUILDX64 (
+    if defined REBUILD ( call "%PCBUILD%build.bat" -p x64 -e -r
+    ) else if not exist "%PCBUILD%amd64\python.exe" call "%PCBUILD%build.bat" -p x64 -e
+    if errorlevel 1 goto :eof
+
+    msbuild "%D%make_pkg.proj" /p:Configuration=Release /p:Platform=x64 %OUTPUT% %PACKAGES%
+    if errorlevel 1 goto :eof
+)
+
+exit /B 0
+
+:Help
+echo build.bat [-x86] [-x64] [--out DIR] [-r] [-h]
+echo.
+echo    -x86                Build x86 installers
+echo    -x64                Build x64 installers
+echo    -r                  Rebuild rather than incremental build
+echo    --out [DIR]         Override output directory
+echo    -h                  Show usage