Each pipe has unique name now. Each pipe can have only one instance.
Attempt to use another pipe name on case of failure.
Wait to complete of pipe initialization.
to search full path of executable. We've considered to let Start
subprogram find full path, but this could be wrong if PATH environment
variable differs in child process environments. So client should find
full path in correct environment with new function Search_Path and pass
full path to Set_Program.
