Fix #67, #68, #71 (hopefully)

[hucario]

67 should be fixed (added perms for hooking onBeforeSendHeaders, sets user-agent)

The way I fixed this should also fix main thread hangs due to synchronous requests. I had to edit a bunch of stuff across multiple files to get that to work.

68 should be fixed due to the same changes that fix #67.

Additionally, I removed/replaced all references to jQuery in background files and newpopup.js, meaning that the only time jQuery is needed should be when you use the old player. Switching to fetch also resolves the warning for using sync xmlhttprequest on the main thread, so that's no longer going to show up on the extensions page.

71 should be fixed due to switching to font icons instead of svg icons using the drop-shadow hack.

I don't have Firefox currently installed, so I can't test it, but I have a Good Feeling:tm: about it.

I also performed a few unrelated fixes / cleanups:

• removed jquery from most of the code
• changed buttons to actual button tags instead of divs for semantics
• changed links to actual a links instead of divs with click listeners for window.open (which don't open into the same frame because I also put a <base target="_blank"> on)
• removed jquery from most of the code
• made a windows port of package.bash for unpackaged/unzipped devving
• removed units from 0 measurements because vscode kept bugging me
• did I mention that I removed jquery from most of the code? pretty hyped about that
• apparently album placeholder colors just... weren't being used, so I fixed that
• there was a vertical separator missing between rows in the theming settings

please keep in mind that the commit messages were an afterthought and aren't grouped sensibly; sorry about that

[pvrs12]

This looks sick. I tested on Firefox and I believe it's working as expected.

I'm noticing one small issue where pausing causes the Play button to disappear. It reappears after closing/re-opening the popup. I'll give it a look, but as you know my frontend knowledge... isn't

No jQuery 🦀 gang

[pvrs12]

Also, as for the commit messages, we can just squash it all down to one cool short one with a lot of 🦀 s

[hucario]

I'm noticing one small issue where pausing causes the Play button to disappear. It reappears after closing/re-opening the popup

fixed

[hucario]

forgot to mention this earlier, but pandora's getStations endpoint apparently just... has an additionalArt parameter so anesidora now uses that to populate the station art initially (also that typo is fixed in case the edit didn't give you a notification; I think we can merge now)