Create widgets

[RaphGL]

Layout

• Box: support border and window title
• Grid
• Flexbox

Components

• Panel
• Button: support mouse click and hover and API to interact with it
• Progress bar
• Text input: single line text buffer
• Text area: multiline text buffer with (optional???) line count
• Scrollbar
• Table
• Paginator
• List selector: permit choosing between single or multiple items
• Spinner: thingy that spins while stuff is loading
• Command palette: builds upon text input and list selector
• Help box: box with possibly no border that has dimmed text used as information for the user