fix 'calendar_return' function in table.py

[inspirit941]

corresponding Function in R is implemented

https://github.com/R-Finance/PerformanceAnalytics/blob/master/R/table.CalendarReturns.R

for (i in 1:length(yearcol[,1])) {
			if(geometric)
				yearcol[i,columnnames[column]] = prod(1 + na.omit(as.numeric(target.df[i,])))-1
			else
				yearcol[i,columnnames[column]] = sum(as.numeric(target.df[i,]), na.rm=TRUE)
			if(yearcol[i,columnnames[column]]== 0) 
                yearcol[i,columnnames[column]] = NA
        }

current function makes ValueError: No axis named 1 for object type <class 'pandas.core.series.Series'>