Move bn_mul.h to library/

Move `include/mbedtls/bn_mul.h` to `library/bn_mul.h`.

Update includes and references to `bn_mul.h` to new location.

Also remove internal headers from `cpp_dummy_build.cpp` as it should only
test public headers in the library.

Signed-off-by: Chris Jones <christopher.jones@arm.com>
diff --git a/visualc/VS2010/mbedTLS.vcxproj b/visualc/VS2010/mbedTLS.vcxproj
index 0e2c060..350eea8 100644
--- a/visualc/VS2010/mbedTLS.vcxproj
+++ b/visualc/VS2010/mbedTLS.vcxproj
@@ -150,7 +150,6 @@
     <ClInclude Include="..\..\include\mbedtls\base64.h" />

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

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

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

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

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

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

@@ -235,6 +234,7 @@
     <ClInclude Include="..\..\tests\include\test\drivers\signature.h" />

     <ClInclude Include="..\..\tests\include\test\drivers\size.h" />

     <ClInclude Include="..\..\tests\include\test\drivers\test_driver.h" />

+    <ClInclude Include="..\..\library\bn_mul.h" />

     <ClInclude Include="..\..\library\check_crypto_config.h" />

     <ClInclude Include="..\..\library\cipher_internal.h" />

     <ClInclude Include="..\..\library\common.h" />