[EPIC] Support interfaces

[0xF6]

• syntax, ast support
• unit tests
• ast->il
• vtables test
• Improvement LD_TOKEN, RuntimeToken and etc  #64
• [vtable improvement] Class bitmap in vtable initialization  #65
• [EPIC] Cast operation #66
• Multiple inheritance #77
• Duplicate Class instance protection #67
• Application Vault - main storage of modules #68
• Natural types (structures and primitives) should be contained in vtable in a raw form #274

public interface IFooBar
{
   method1(): void;
   method2(arg: Int32): void;
}