Make script function safer and simpler to use

[ttytm]

This PR updates the script method that calls javascript and returns a response.

The current implementation strips away the simple possibility of the parent C API to check if the script has run successfully.

It re-implemets this possibility for the script method and makes it safer and simpler to use.

• The only arguments for the method will be the java script code string
• The params timeout and the response buffer size max_response_size (defaults to 8KiB) become optional.

  // New default
  resp := e.window.script('return count;')
  // Instead of default
  resp := e.window.script('return count;', 0, 4096)
  // Now, if a timeout should be added
  resp := e.window.script('return count;', timeout: 10)

• It will return a ScriptResponse inspired by Vs builtin os.execute. This contains a success and a output filed. It can be used with e.g. resp.success to check if it the script has run successfully and res.ouput to get the output.

[ttytm]

ok instead of success is probably a better field name.

[hassandraga]

Actually, I vote for success. It makes the code more readable. Unless 'ok' is common and I don't know.

[ttytm]

Success then it should be!

[hassandraga]

LGTM