Add test on Windows for symlink

[imlucas]

As reported in mongodb-js/runner#81

This is a simple fix. The path appears to be missing a \. Should be C:\Users\Steven Shipton\.mongodb\versions\mongodb-3.0.8-windows-64 instead of C:\Users\Steven Shipton.mongodb\versions\mongodb-3.0.8-windows-64

{ [Error: EPERM: operation not permitted, symlink 'C:\Users\Steven Shipton.mongodb\versions\mongodb-3.0.8-windows-64' -> 'C:\Users\Steven Shipton.mongodb\versions\mongodb-current']
errno: -4048,
code: 'EPERM',
syscall: 'symlink',
path: 'C:\Users\Steven Shipton.mongodb\versions\mongodb-3.0.8-windows-64',
dest: 'C:\Users\Steven Shipton.mongodb\versions\mongodb-current' }

[steven-supersolid]

I wonder if the space in the username is causing the issue or the path is just missing the ?