Implemented architecture detection for Windows chrome executable, so tha...

This one is a little better than the last pull request.

Implemented architecture detection for Windows chrome executable, so that 32-bit and 64-bit windows each have their own (hopefully correct) path.

If you have a custom path to Chrome in your user settings and use 64-bit Windows, you must use the key "windows_x64" instead of "windows" for the chrome_path.