Validate Program entry points and resolve accessible zero-argument constructors

tests/include_statements.aer

@@ -3,7 +3,7 @@ require 'data/includes/test_class.aer';
 
 class Program extends BaseClass {
 
-	void main() {
+	public void main() {
 		$this->run();
 		object $test = new Test();
 		var_dump($test);

tests/is_statement.aer

@@ -7,7 +7,7 @@ class Test2 extends Test1 {
 
 class Program {
 
-	void main() {
+	public void main() {
 		int[] $q = {1, 2, 3};
 		float $t = 4;
 		object $x = new Test1();

tests/sudoku_solver.aer

@@ -79,7 +79,7 @@ class Sudoku {
 
 class Program {
 
-	void main() {
+	public void main() {
 		int[] $board = {
 			{3, 0, 6, 5, 0, 8, 4, 0, 0},
 			{5, 2, 0, 0, 0, 0, 0, 0, 0},