Fixed choosing the right version of Visual Studio

Fixes #68
Fixed process tests on Windows
Fixed Windwos symlinks issues in tests

Symlinks are only allowed in elevated mode, see
https://github.com/joyent/libuv/blob/da71649991029bcfabc429b26685bf17bb3d48d1/test/test-fs.c#L1266
Fixed IPC tests on Windows
Fixed multicast tests on Windows and Linux