Fixed a bug in AbstractTool class that could cause a severe slow-down on process...

Fixed a bug in AbstractTool class that could cause a severe slow-down on process creation, especially with a large number of threads: The same mutex was used in the constructor and the startProcess() function, which is unnecessary anyway. But even worse, there was a sleep() call in the startProcess() function that could *block* the mutex for a very long time! So if the "main" thread tried to create a new object while one of the "worker" threads was sleeping inside startProcess(), this blocked the whole "main" thread. D'oh!