fix day-of-week timestamp bug in insert-dashboard-cat filter.

I didn't realise the local-time system set 'Sunday' to '0' in its
timestamp-day-of-week function. I thought it was '7'. This commit changes the
check for '7' to '0' and adds a few comments to help identify which days the cond
form is checking against.

src/view.lisp

@@ -110,12 +110,16 @@
 	   (format nil "/images/icons/study-cat.png"))
 	  ((and (>= (local-time:timestamp-hour timestamp) 18)
 		(< (local-time:timestamp-hour timestamp) 20))
-	   (cond ((<= (local-time:timestamp-day-of-week timestamp) 5)
-		  (format nil "/images/icons/workout-cat.png"))
-		 ((= (local-time:timestamp-day-of-week timestamp) 6)
-		  (format nil "/images/icons/rock-star-cat.png"))
-		 ((= (local-time:timestamp-day-of-week timestamp) 7)
-		  (format nil "/images/icons/love-cat.png"))))
+	   (cond
+             ;; Sunday
+             ((= (local-time:timestamp-day-of-week timestamp) 0)
+	      (format nil "/images/icons/love-cat.png"))
+             ;; Monday - Friday
+             ((<= (local-time:timestamp-day-of-week timestamp) 5)
+	      (format nil "/images/icons/workout-cat.png"))
+	     ;; Saturday
+	     ((= (local-time:timestamp-day-of-week timestamp) 6)
+	      (format nil "/images/icons/rock-star-cat.png"))))
 	  ((and (>= (local-time:timestamp-hour timestamp) 20)
 		(< (local-time:timestamp-hour timestamp) 22))
 	   (format nil "/images/icons/dinner-cat.png"))