Add all sources and update README.md and .gitignore
Rename some fields in GuiButton
Create GuiButtonClear and change main menu buttons to them
Make panorama background on multiplayer and singleplayer menu
Change language button text to nothing
Make options have the panorama background too
Remove glitched scrollbar from clear guislots
Make scrollwheel less terrible to use
Make a lot more guiscreens have the panorama background
Also fix guislotclear elements getting rendered when they shouldn't (like under other buttons)