Repository improvements

[jputcu]

Hello,

A few questions:

• Is support/avr-stl-1.1.1.zip still being used? It is taking up almost 200kb?
• Wouldn't it be better to replace support/Release notes.txt with a more conventional CHANGELOG.txt/md/... in the root?
• Perhaps a hint to a nice changelog format https://keepachangelog.com/en/1.0.0/

[jwellbelove]

Sorry for the delayed response! I don't get any notifications to new discussion topic!
I'll take a look at your suggestions.

[jwellbelove]

I've removed the AVR STL zip file.