This isn't relevant anymore because steam has just rolled out the new library https://store.steampowered.com/libraryupdate
This is how you install it, thanks Colek38 for the files!
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Download this: steamui.zip
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Open that zip and extract the folder steamui (as it is!) in the root directory of your steam installation (where steam.exe is) > https://i.imgur.com/BwYAsZ4.png
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Create shortcut of said steam.exe
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Edit the shortcut by appending -newlib to it. Look at this > https://i.imgur.com/meJc1AX.png
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Exit Steam (don't restart, press Exit)
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Open steam with that new shortcut
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Profit?
If you want steam library update on startup use this registry edit
Edit manually https://i.imgur.com/4lL4McT.png or edit automatically with this steamui.reg