1. Bug fixes:
      a. Budget_utils is now a module.  Some compilers do not like
          when functions have pointers as arguments, unless they are inside 
          a module.
      b. In disturbance.f90, variable mask was not allocated when
          cpatch%ncohorts was zero, so the debugger would crash if it tried 
          to use mask.
      c. In average_utils.f90, daylight was used in divisions, but 
          the number can be zero- this should happen only in polar 
          nights so it should be fixed.
      d. Several disturbance-related variables were not properly set 
          to zero, leading to some crazy values in the big leaf model 
          whenever fires happened.
2. Added some diagnostic variables (means and mean sum of squares, 
          mostly radiation and u*)
3. Modified INCLUDE_FIRE = 3, now the water deficit threshold is 
          relative to the total rainfall instead of the absolute number.
4. Corrected some R scripts