Assume private visibility for all class members by default.

In most (all?) modern OOP languages class members visibility is assumed to be private and programmer has to consciously set it to public or protected. PHP has the different approach what can cause a security flaws in written scripts. AerScript will not follow this way, as it seems to be conceptually broken.

tests/multiple_inheritance.aer

@@ -53,7 +53,7 @@ class TestE {
 
 class Program extends TestE, TestD, TestC, TestB, TestA implements IntA, IntB {
 
-	void main() {
+	public void main() {
 		$this->test_a();
 		$this->test_b();
 		$this->test_c();