New GUI implementation panel width

New GUI implementation that I tested for Omid did not have any issues with functionality that I observed in testing.

The one issue observed is the panels change width depending on content/selection in a way that is distracting. In particular, the tree section on the left-hand side should be set to a constant width. If nothing is selected, it fills the entire screen width, and upon selecting a station/channel, decreases in size to allow the right panel with the station/channel details to open. Even when the station panel is open, the tree panel is a little wider than necessary and could probably be set to a width such that every column is visible, but the empty space is minimized.