Adding Task Manager

[aliireza]

I think a better design would be to define a task manager class that performs tasks instead of handling them in the main function (it can use a queue or a stack). By doing so, initially, the main application submits two tasks: (i) "If there is no main, add it and use this code. If there are compilation errors, fix all of them" and (ii) perform the input task. Optionally, there might be performance-related and correctness-related tasks. This will make it possible to handle all AI interactions from one location in the code. Currently, performance_checker uses both compile_checker and the AI model to generate a benchmarking code.