Test support for windows

[phated]

To get exec to work on windows, something special needs to be done. Not sure what it is. Also need to update current tests.

[heikki]

Hey, do you mean these errors?

This is the closest explanation I could find: requirejs/r.js#369 (comment)

Exec tries to run index.js with Windows Script Host.

[heikki]

Above thing can be fixed by adding node to exec commands.

child.exec('node ' + __dirname + '/../index.js --tasks --cwd ./test', function(err, stdout) {

After that there's issues with line endings and stdout truncating.

Some projects, for example grunt, use node-exit to fix stdout problem. I'll have to dig further to see what actually needs that fix.

[phated]

Fixed by #4