have option to pass in sauce connect timeout from config

Previously I saw no way to pass in the sauce connect timeout when using the rspec setup. Hopefully this will make setting the timeout a little more accessible. 

You can set the timeout in your Sauce.config, or you can pass the timeout as an arg for those who start a sauce-connect manually.

#Usage:
```
Sauce.config do |config|
  config[:sauce_connect_timeout] = 120
end
```

or

```
Sauce::Connect.new({:sauce_connect_timeout => 120})
```

This will break the existing code if anyone was starting a sauce connect using `Sauce::Connect.new({:timeout => 100})`. I didn't want to name the key `:timeout` as it will not be clear what the `:timeout` key does in the `Sauce.config`

Would like some feedback on this. Thanks