Read directory in seperate thread

[Rekrul]

I have one directory with a very large number of files in it and TC can take a very long time to read that directory. While it is doing this, the whole program is in limbo. It would be nice if a separate thread was used for this so that I could still access the other tabs while it's working. At the very least, I should be able to access the other panel at the same time if not switch tabs in the same panel.