Add with options (#39)

[ninoseki]

Add with options to do #39.

To be honest, I'm not sure whether this is the cleanest solution for #39 but it works like the following:

# wait and download a DOM
urlscan scan submit <url> --with-dom
# wait and download a screenshot
urlscan submit <url> --with-screenshot
# wait and download both
urlscan submit <url> --with-both

[cdnsyseng]

Suggested change

	--with-both Download both a screenshot and a DOM (this flag overrides wait, with-screen and with-both flags to true)
	-d, --download Download screenshot and DOM contents (overrides wait/dom/screenshot)

[ninoseki]

Fixed by c13f3a4

[cdnsyseng]

Suggested change

	--with-dom Download a DOM (this flag overrides wait flag to true)
	--dom Download only the DOM contents (overrides wait)

[ninoseki]

Same as the above (c13f3a4)

[cdnsyseng]

Suggested change

	--with-screenshot Download a screenshot (this flag overrides wait flag to true)
	--screenshot Download only the screenshot (overrides wait)

[ninoseki]

Same as the above (c13f3a4)

[cdnsyseng]

I think the flag names and descriptions could be improved. I didn't change other places in code in case we decide against the suggested changes.

IMHO, there is no need to specify --with- because including the flag implies the operation.

[heipei]

Didn't we agree in #39 that submit would just submit and return the UUID and that perform would block and wait and download the results?

[ninoseki]

@heipei

• submit already has --wait option before Feature request: UUIDs are annoying #39
• How to implement Feature request: UUIDs are annoying #39 is keep remaining as an open question (as far as I know)

But anyway I will split the functionality into perform if you think that is cleaner than this implementation.