Cleaned up the code. Also, text is now drawn in gray (following the
pattern of our mockup).
Separators are now 5-pixel-high gray rectangles instead of thin blue
lines.
Changed methods so that now we just have Calendar objects for start and
end dates encompassing the time we want drawn. The background draws
correctly as long as start dates and end dates are within the same year.
Also added text for the day of the week (short names: "Mon", "Tues,
etc.)
Removed unused import statements