set RuntimeLibrary for zlib project to default

vsprojects/vs2013/third_party/zlibvc.vcxproj

@@ -58,7 +58,6 @@
       <PreprocessorDefinitions>WIN32;_CRT_NONSTDC_NO_DEPRECATE;_CRT_SECURE_NO_DEPRECATE;_CRT_NONSTDC_NO_WARNINGS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <ExceptionHandling>
       </ExceptionHandling>
-      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <PrecompiledHeaderOutputFile>$(IntDir)zlibvc.pch</PrecompiledHeaderOutputFile>
       <AssemblerListingLocation>$(IntDir)</AssemblerListingLocation>
@@ -110,7 +109,6 @@
       <StringPooling>true</StringPooling>
       <ExceptionHandling>
       </ExceptionHandling>
-      <RuntimeLibrary>MultiThreaded</RuntimeLibrary>
       <BufferSecurityCheck>false</BufferSecurityCheck>
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <PrecompiledHeaderOutputFile>$(IntDir)zlibvc.pch</PrecompiledHeaderOutputFile>