update to the manual adding images for ToD

...and adding the description for underground

(esr, please check if that works okay)

doc/manual/manual.txt

@@ -511,16 +511,20 @@ The following table shows the effects of different times of the day on
 the damage dealt by lawful and chaotic units:
 
 .Time of the day and damage
-`-----`----------------------------------`---------------------`-------`------
-Turn  Image                              Day-phase             Lawful  Chaotic
-------------------------------------------------------------------------------
-1     image:images/time-dawn.png[]       Dawn                  --      --     
-2     image:images/time-morning.png[]    Day (morning)         +25%    -25%   
-3     image:images/time-afternoon.png[]  Day (afternoon)       +25%    -25%    
-4     image:images/time-dusk.png[]       Dusk                  --      --     
-5     image:images/time-firstw.png[]     Night (first watch)   -25%    +25%   
-6     image:images/time-secondw.png[]    Night (second watch)  -25%    +25%   
-------------------------------------------------------------------------------
+`-------`----------------------------------------`---------------------`-------`------
+Turn    Image                                    Day-phase             Lawful  Chaotic
+--------------------------------------------------------------------------------------
+1       image:images/schedule-dawn.jpg[]         Dawn                  --      --     
+2       image:images/schedule-morning.jpg[]      Day (morning)         +25%    -25%   
+3       image:images/schedule-afternoon.jpg[]    Day (afternoon)       +25%    -25%    
+4       image:images/schedule-dusk.jpg[]         Dusk                  --      --     
+5       image:images/schedule-firstwatch.jpg[]   Night (first watch)   -25%    +25%   
+6       image:images/schedule-secondwatch.jpg[]  Night (second watch)  -25%    +25%
+Special image:images/schedule-underground.jpg[]  Underground           -25%    +25%
+--------------------------------------------------------------------------------------
+
+Keep in mind that some scenarios take place underground, where it is 
+perpetually night!
 
 For example: consider a fight between a Lawful and a Chaotic unit when
 both have a base damage of 12. At dawn and dusk, both will do 12 points