Normalize \\ paths to / on windows based systems. Makes all tests pass

[Havunen]

Fixes github #1

NodeJS resolve returns \ for paths in windows based systems and / for posix. This PR fixes the failed tests in this repository when running on windows.

This is the problem:

path.join('foo', '..', 'bar', 'baz/foo');
// 'bar/baz/foo' on OSX and Linux
// 'bar\\baz\\foo' on Windows

path.resolve('../', '/../', '../')
// '/home' on Linux
// '/Users' on OSX
// 'C:\\Users' on Windows

See https://shapeshed.com/writing-cross-platform-node/