Unique zyre windows export macro.
The macro cannot be shared between projects, as that would mark the symbols as being imported even
though this project defines them
Casts and stdlib changes for Windows.
Windows does not have strdup, and complains about void* -> type* conversions
Windows 2012 solution & project files

also updated .gitignore to ignore windows build artifacts
Merge pull request #211 from twhittock/master

Changes to alloww for compiling on Windows