Changes for VS2010 about czmqpp

[evoskuil]

@HughPowell Thanks for doing the work to expand usability below C++11. This was written for czmq integration with libbitcoin's Obelisk by @genjix, and that code utilizes latest compiler features, but for more general use with zmq it's better to keep it at a lower compiler version. We were planning to add exports, so it's great that you've done this too.

There are a couple of issues in the project/props files. I would ask that you create a pull request for the cpp changes and I'll expand the VC project coverage to vs2012 and vs2010 once we have verified the build.

[HughPowell]

C++ changes in #8

[evoskuil]

@HughPowell Do the exports compile properly for you in a DLL build?

[HughPowell]

@evoskuil Sorry, forgot to include the changes to the preprocessor definitions which were to include LIBCZMQ_EXPORTS for the DLL builds. Looks like you've taken care of all that with #9
Cheers

[evoskuil]

Yes, it all looks good presently. Thanks for making the changes to expand this to v100 and v110 as well as dynamic linking! Note that libsodium has adopted the three platform builds that follow the same pattern, so everything should work well once the libzmq pull request is merged.