Hi @abit,
Since you are reviewing codes. Can you look at these errors?
When I am Compiling v0.14.3rc1 with VS2013.
I encounter two ambiguous call to overload function errors:

I believe the errors were introduced on issue #476.
https://github.com/steemit/steem/commit/3920af70cabb9f05b460b25a12a4191d35daddbc
The compiling log is long, this is partial log.
Thank You.

1). error C2668: 'fc::from_variant' : ambiguous call to overloaded function

          F:\Git_GUI\steem\libraries\fc\include\fc/reflect/variant.hpp(53): error C2668: 'fc::from_variant' : ambiguous call to overloaded function
          F:\Git_GUI\steem\libraries\chain\include\steemit/chain/protocol/operations.hpp(95): could be 'void fc::from_variant(const fc::variant &,steemit::chain::operation &)'
          F:\Git_GUI\steem\libraries\chain\include\steemit/chain/protocol/asset.hpp(123): or       'void fc::from_variant(const fc::variant &,steemit::chain::asset &)'
          F:\Git_GUI\steem\libraries\chain\include\steemit/chain/protocol/version.hpp(74): or       'void fc::from_variant(const fc::variant &,steemit::chain::hardfork_version &)'
          F:\Git_GUI\steem\libraries\chain\include\steemit/chain/protocol/version.hpp(71): or       'void fc::from_variant(const fc::variant &,steemit::chain::version &)'
          F:\Git_GUI\steem\libraries\chain\include\steemit/chain/protocol/types.hpp(269): or       'void fc::from_variant(const fc::variant &,steemit::chain::extended_private_key_type &)'
          F:\Git_GUI\steem\libraries\chain\include\steemit/chain/protocol/types.hpp(267): or       'void fc::from_variant(const fc::variant &,steemit::chain::extended_public_key_type &)'
          F:\Git_GUI\steem\libraries\chain\include\steemit/chain/protocol/types.hpp(265): or       'void fc::from_variant(const fc::variant &,steemit::chain::public_key_type &)'  

2). error C2668: 'fc::raw::unpack' : ambiguous call to overloaded function

F:\Git_GUI\steem\libraries\fc\include\fc/io/raw.hpp(292): error C2668: 'fc::raw::unpack' : ambiguous call to overloaded function
          F:\Git_GUI\steem\libraries\fc\include\fc/uint128.hpp(131): could be 'void fc::raw::unpack<fc::datastream<const char *>>(Stream &,fc::uint128 &)'
          with
          [
              Stream=fc::datastream<const char *>
          ]
          F:\Git_GUI\steem\libraries\fc\include\fc/io/raw.hpp(583): or       'void fc::raw::unpack<boost::container::flat_map<std::string,steemit::chain::weight_type,std::less<_Kty>,boost::container::new_allocator<std::pair<Key,T>>>>(const std::vector<char,std::allocator<char>> &,boost::container::flat_map<Key,T,std::less<_Kty>,boost::container::new_allocator<std::pair<Key,T>>> &)'
          with
          [
              _Kty=fc::string
  ,            Key=std::string
  ,            T=steemit::chain::weight_type
          ]