(File)hashing Speedup (#enhancement)

[sammy2k8-lab]

hi guys
ive seen the (file)hashing algorithm does use only one cpu core at time.

how about using more cores, optimize this crucial part for multi thread?

easy idea: a option to manual set core count, so the user could give system resources
optimal way: automatic detect core count

-> the os scheduler does the job for loadbalancing
-> every raspberry or intel celeron does have 4 cores+

thanks for your good work, looking forward to get QT6 version compiling at Suse OBS.
sammy2k8