* Upgraded to Visual Studio 2013

* Upgraded to Visual Studio 2013
* Notable changes needed because of boost upgrade:
  - custom async implementation removed in favor of std::async. (boost::async still does not have support for deferred launch policy).
  - std::future instead of boost::future throughout the code because of above change.
  - std::future requires default constructibility, so for example caspar::array has been affected. spl::shared_ptr has been changed to std::shared_ptr in cases where required.
  - boost.log changes adopted from 2.0.7.
* Fixed bugs where some OpenGL resources was not destructed on ogl thread.
* Fixed audio cadence issues in ffmpeg producer.