Create 05_MaxSubmatrixFinder.cs

05. Write a program that reads a text file containing a square matrix of numbers and finds in the matrix an area of size 2 x 2 with a maximal sum of its elements. The first line in the input file contains the size of matrix N. Each of the next N lines contain N numbers separated by space. The output should be a single number in a separate text file.
 Example:
 4
 2 3 3 1 
 2 3 4 1    ->17
 3 7 1 2
 4 3 3 2