Features
* A thread pool implementation by C language
* It is very simply to use the thread pool, just need to include threadpool.h in your code
* Start all threads on creation of the thread pool
* Adding task can be in blocking way or noblocking way
* Destory thread pool can be in wait_for_active_tasks way or immediately way
Future Work
* Change dynamicly the size of thread pool
* Policy-based thread pool
* Add more destory thread pool policy
Test
$make
$./test/test_tp_main
$sh test/repeat_run_test_tp_main.sh