C++11 Thread Pool implementation

use:

1. your class extends Thread and implements run and endRun methods
2. create threads pool: ThreadPool<MyClass> threadPool;
3. get thread if available else wait: MyClass &myThread = threadPool.getNextThread()
4. execute run method: myThread.start()

example:

    ThreadPool<MyClass> threadPool;
    threadPool.setNthread(4);//max 4 running threads
    for (int i = 0; i < 100; i++) {
        MyClass &myThread = threadPool.getNextThread();
        myThread.start();
    }
    threadPool.joinAll();

test directory contains an example, how to find prime numbers from 0 to 100,000 spreading the work on many threads, to compile:

cd test && g++ -pthread -O3 -DDLOG_LEVEL=_INFO -std=c++11 main.cpp MyClass.cpp ../util/String.cpp -o find_prime_number

./find_prime_number N_THREADS