Update lua df time class. Fix refs

Author: dhdnd88

depends/googletest

@@ -31,6 +31,9 @@ end
 function Time:getDays() -- >>float<< Days as age (including years)
  return self.year * 336 + (self.ticks / TU_PER_DAY)
 end
+function Time:getDayInYear() -- >>int<< Current day of the year
+ return math.floor (self.ticks / TU_PER_DAY)
+end
 function Time:getDayInMonth()
  return math.floor ( (self.ticks % TU_PER_MONTH) / TU_PER_DAY ) + 1
 end
@@ -58,16 +61,27 @@ function Time:getDayStr() -- Day as date
  end
  return d
 end
---function Time:__add()
---end
+function Time:__add(other)
+ if DEBUG then self:_debugOps(other) end
+ if self.ticks + other.ticks > TU_PER_YEAR then
+  -- We add a year when ticks delta is greater than a year.
+  return Time{ year = (self.year + other.year + 1) , ticks = (self.ticks + other.ticks - TU_PER_YEAR) }
+ else
+  return Time{ year = (self.year + other.year) , ticks = (self.ticks + other.ticks) }
+ end
+end
 function Time:__sub(other)
- if DEBUG then print(self.year,self.ticks) end
- if DEBUG then print(other.year,other.ticks) end
+ if DEBUG then self:_debugOps(other) end
  if self.ticks < other.ticks then
+  -- We subtract a year when ticks delta is less than a year.
   return Time{ year = (self.year - other.year - 1) , ticks = (TU_PER_YEAR + self.ticks - other.ticks) }
  else
   return Time{ year = (self.year - other.year) , ticks = (self.ticks - other.ticks) }
  end
 end
+function Time:_debugOps(other)
+ print(self.year,self.ticks)
+ print(other.year,other.ticks)
+end
 
 return _ENV