0024157: Parallelization of assembly part of BO

0024157: Parallelization of assembly part of BO
New metod was implemented to class BOPAlgo_Builder
   - method:
void BOPAlgo_Builder::SetRunParallel(const Standard_Boolean theFlag)
The method sets the flag of parallel processing
 if <theFlag> is true  the parallel processing is switched on
 if <theFlag> is false the parallel processing is switched off
  - method:
Standard_Boolean BOPAlgo_Builder::RunParallel()const
The method returns the  flag of parallel processing

Class BOPTest was changed
   - static function:
Standard_Integer bbuild(Draw_Interpretor& di, Standard_Integer n, const char** a)
The optional parameters [ -s -t ] have been added to the command line of
the command 'bbuild':
bbuild r [-s -t]
-s : builds the result using serial procesing
-t : show the wall time