Feature: Fire terminal resize events.
For windows (WINDOW_BUFFER_SIZE_EVENT): 
https://docs.microsoft.com/en-us/windows/console/reading-input-buffer-events

For linux (SIGWINCH)

As a fallback:

```nim
var oldDimenions = terminalSize()
tb = newTerminalBuffer()
if oldDimenions != terminalSize():
  tb = newTerminalBuffer(terminalSize().w, terminalSize().h)
  oldDimenions = terminalSize()
```