Progress: controller program and f_thread.

Progress: controller program and f_thread.

Add more mutex lock protections.
The thread->data->child is shared and cannot be used as a per thread child process storage, so comment out and add an @fixme.

In the case where the exec() functions return in the child process, the mutexes may not be fully trusted.
All the child process should do is find its way to the exit, deallocating along the way.
Avoid all mutex-related and printf() related functionality where possible.
There were some places where the F_child is not being checked for and returned on but should be checked for and rreturned on.

Work towards improving the mutex locking logic when working with the asynchronous processes, caching, and cancelling.
There is more work to do in this regard.

Sleep interval for the cache cleanup thread now uses the short timer when in test mode and the long timer in non-test mode.

Add a list of functions that need to be completed for t_thread.
Add f_thread_mutex_attribute_t and f_thread_mutex_attributes_t related functions.
Minor cleanups in f_thread.