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.
Yes I tried that, and it works.

The reason I kept the extension in the code is because when you download the executable file and saving the stream to a file were you don't have an extension in Windows, then will the file not be recognized as an application and you dont see any icon. 
And that look confusing when you browse in the explorer view in the directory were you downloaded the BrowserStackLocal.exe to.