Update Visual Studio project files

This commit updates the Visual Studio project file
`visualc/VS2010/mbedTLS.vcxproj` to add the newly
introduced `rsa_internal.h` and `rsa_internal.c`.
diff --git a/visualc/VS2010/mbedTLS.vcxproj b/visualc/VS2010/mbedTLS.vcxproj
index 65730cd..f13f83c 100644
--- a/visualc/VS2010/mbedTLS.vcxproj
+++ b/visualc/VS2010/mbedTLS.vcxproj
@@ -199,6 +199,7 @@
     <ClInclude Include="..\..\include\mbedtls\platform_time.h" />

     <ClInclude Include="..\..\include\mbedtls\ripemd160.h" />

     <ClInclude Include="..\..\include\mbedtls\rsa.h" />

+    <ClInclude Include="..\..\include\mbedtls\rsa_internal.h" />

     <ClInclude Include="..\..\include\mbedtls\sha1.h" />

     <ClInclude Include="..\..\include\mbedtls\sha256.h" />

     <ClInclude Include="..\..\include\mbedtls\sha512.h" />

@@ -267,6 +268,7 @@
     <ClCompile Include="..\..\library\platform.c" />

     <ClCompile Include="..\..\library\ripemd160.c" />

     <ClCompile Include="..\..\library\rsa.c" />

+    <ClCompile Include="..\..\library\rsa_internal.c" />

     <ClCompile Include="..\..\library\sha1.c" />

     <ClCompile Include="..\..\library\sha256.c" />

     <ClCompile Include="..\..\library\sha512.c" />