Started Building GUI

Created the 9x9 grid using a 3x3 JPanel that holds 9 other 3x3 JPanels.
These hold TextCells.  TextCells now have the Center Alignment.  Can't
seem to get them to only accept a single Integer.  Also, need to add a
bigger font.  Also, need to change the main layout so that when the
window resizes the grid doesn't resize with it.  Possibly need to use
GridBagLayout.  Before I do any of that I need to add comments to what I
have.  Lastly, need to add in a way to easily obtain the text in the
cells.