Windows fixes

Changed to BrowserStackLocal.exe instead of the jar-file.
The tunnel process is now killed when the tests are complete.
Before when using the jar-file the tunnel processes still were alive in the background after the test were completed. Which created problem the next time you ran the tests, your worker then never received the "Acknowledge" state,

Added path fix for Windows, it now works with "/" on Windows in the "test_path" config.

Fixed the Process signals to work on Windows, before you never got to the method "cleanUpAndExit" in cli.js because of how Process.kill works on Windows. It now runs "cleanUpAndExit" before exiting the process as expected.
I still feel like we're not talking about the same thing. Consider this (fake console example):

```sh
$ dir
BrowserStackLocal.exe
$ BrowserStackLocal
Executes BrowserStackLocal.exe
```

Note that the second command doesn't specify the extension, but finds the file anyway.

Now if the file is named `BrowserStackLocal.exe`, what happens in node when you run `execFile("BrowserStackLocal")`?