@todo add licence (MIT, same as ImGui)
@todo add vttest
@todo pass vector<uint32_t> to commands?
@todo problem with reverse after blink? (should reverse turn off blink?)
@todo do we need attributes for lines (for dwl, dhl, etc)?
@todo check erase vs fill editing operations for attributes - do we clear on erase and use current for fill?
@todo split visual attributes from others?

@todo state levels:
   - Terminal
   - Session
   - Window?
   - Screen? (xterm does multiple)