Add Color fields to BuildableStackedSlide

I'll be removing the ColorScheme from the BSS constructor, instead
providing the user the ability to select colors for each component.
BuildableStackedSlide: remove ColorScheme from constructor
Obtain FontMetrics from new Canvas()

This eliminates the need for a Graphics object when determining font
size. I still might look into obtaining a GraphicsConfiguration from the
display module (although GC is not serializable).
Add center and wideThird flags
Add buffer manipulation methods to BuildableStackedSlide
Add BuildableStackedSlide.SIDE_MARGIN
wideThird is not really necessary

My method here will be to draw the outside columns, then shrink the
inside column(s) as needed to fit in the remaining space. Thus, I don't
need to specify the width of one of the columns.
Add FontUtils and shrinkFontForWidth
Add HORIZ_SPACER to BuildableStackedSlide
shrinkFontForWidth is now static
Add Chunk.draw and implement for all the chunks in BSS

That...was a doozy.

On the bright side, I'm basically done with Graphics code--I just need
to add all the "glue" that turns these Chunks into a working
implementation, then make the SlideLists use these BuildableStackedSlide
contraptions correctly.

Of course, I'm not done with Swing GUI code...

...and this BSS is untested and could sputter and die, just like the
rest of my graphics code...