Add the quiet flag

[Richard-Rogalski]

Adds a new option that will only return the URL and nothing else to stdout on a successful run.

This has a few uses:

• Enables piping the output URL into other programs
• Much easier to copy from most term emulators (double click the line, instead of carefully selecting only the link)

I made the --quiet flag only have an affect on a successful run, but if it would make more sense for it to also output nothing on failure, I could do that too.

[Richard-Rogalski]

Oh look, and Closes: #19

[xxc3nsoredxx]

I'd also squash the indentation fix commit.

[Richard-Rogalski]

New unbroke PR: #51