Add an HKDF (RFC 5869) implementation
diff --git a/visualc/VS2010/mbedTLS.vcxproj b/visualc/VS2010/mbedTLS.vcxproj
index 802cce7..4c5c480 100644
--- a/visualc/VS2010/mbedTLS.vcxproj
+++ b/visualc/VS2010/mbedTLS.vcxproj
@@ -178,6 +178,7 @@
     <ClInclude Include="..\..\include\mbedtls\error.h" />

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

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

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

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

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

     <ClInclude Include="..\..\include\mbedtls\md2.h" />

@@ -248,6 +249,7 @@
     <ClCompile Include="..\..\library\error.c" />

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

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

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

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

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

     <ClCompile Include="..\..\library\md2.c" />