Actor system first version

Features the first version of the actor system. Incorporates actors which can send and receive messages through named endpoints.
This version also replaces Javascript prototype-based object system by a class-based object system.
Objects prototypes have proven to be problematic when you want 'deep frozen' objects (object which are immutable and contains no direct or indirect references to mutable objects.

Complete Javascript engine

This version features a Javascript engine which functionality is equivalent to TinyJS (except for non-standard behaviours detected)
However, the code has been almost completely rewritten for better scalability. Those components have been added / replaced:

• New lexical analyser.
• New parser, which just parses the code. It is not mixed with the execution engine.
• New abstract syntax tree.
• New Javascript data types support code.
• New execution engine, based on a byte code executing virtual machine.
• And a new code generator which generates code for the virtual machine.

No specific AsyncScript features yet.