Fixed deprecated module, whitespace, booleans and other small tidyups

[marksmayo]

Lots of whitespace, cleanups
simplified if conditions
Cleaned up imports (using isort)
fixed use of deprecated imp module

[soimort-bot]

Hello @marksmayo,
Thanks for the Pull Request. We ❤️ our contributors!
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[archz2]

Sorry to write about the issue I'm facing in someone elses's thread but I'm not able to create a new pull request thread. The button remains faded out.

I'm trying to download a video on bilibili in 1080p resolution but it always gets downloaded in 480p.

I use the following command.

you-get -format=flv https://www.bilibili.com/video/BV1W8411b7K5/?p=5&share_source=copy_web&vd_source=14d801274def2dd112297a8c82660e8c

In the usage given here, https://github.com/soimort/you-get#getting-started

There's a mention of itag. However, when I use the -i command, I don't get any itags.

Please suggest a solution.