NEW: Add test.c to test functions

Added testing file to test each project function before release.

test.c

+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include "grid.h"
+
+int main01()
+{
+    // Test des fonctions creer_grid() et free_grid() dans grid.c
+    int row = 11;
+    int column = 26;
+
+    grid* level = creer_grid(row, column);
+    level->game_grid[0][0] = '#';
+    level->game_grid[3][1] = '@';
+
+    printf("Size of structure is %d\n", (int)sizeof(*level));
+    printf("Number of lines is %d\n", level->row_number);
+    printf("Number of columns is %d\n", level->column_number);
+    printf("Grid block at coordinates (0,0) %c\n", level->game_grid[0][0]);
+    printf("Grid block at coordinates (1,3) %c\n", level->game_grid[3][1]);
+
+    free_grid(level);
+    return 0;
+}
+
+int main() {
+    // Test de la fonction init_level() dans grid.c
+    grid* level = init_level("level1.txt");
+
+    printf("Number of lines is %d\n", level->row_number);
+    printf("Number of columns is %d\n", level->column_number);
+    printf("Grid block at coordinates (12,5) %c\n", level->game_grid[5][12]);
+    printf("Grid block at coordinates (7,2) %c\n", level->game_grid[2][7]);
+
+    free_grid(level);
+    return 0;
+}