Handle library window resize correctly

# Understand how Winamp Works

## Definitions:

- **Window** The draggable Winamp window
- **Left Pane** The resizable section on the left that enumerates different media sources
- **Track Area** The resizable area on the right which shows different media track. May be divided into up to three panes.
- **Upper Track Area** The resizable top portion of the Track Area which is devided into two resizable columns
- **Track Columns** The resizable columns in the Track Area panes which

## Observations

- When resizing the window, the Left Pane size stays constant. The panes in the Track Area resize proportionally
- When resizing the window, the Track Columns do not resize
- If resizing the window causes scrollbars to appear/disappear in any pane, that size is taken from the pane itself.
- The sidebar has a minimum size. Below that it collapses to zero. The presense of a scrollbar does not affect this.
- The sidebar has a maximum size.
- Each of the panes in the Track Area has a minimum size. The Track Columns minimum size is greater than the others.