Multitasking

The main code of Scheduler service has been finished.

Features:
* Priorities;
- Rare priority - run only when other processes are not running;
* Locking;
* Event code vs main code scheduling - supports processes that consist of these two parts;

At the moment this Scheduler is designed for single-processor computers, but its design allows to modify it to support multi-processor architectures rather simply.

The next job is going to be to write a Service controller. Service controller is the main process that implements sending messages between processes. It also supports dinamic libraries. I will discuss this later in my posts.