Make robocopy regex compatible with languages other than english

[jantari]

I noticed on machines using a system language other than english, the folder sizes when using -UseRobo were all returning 0.

Looking into it, this was because the $expectedSummary regex did not match the output from non-english robocopy versions (yes, unfortunately Microsoft localizes many CLI tools in Windows ...)

I adapted the Regex to so that it should handle most languages.

A sample output from german robocopy is:

------------------------------------------------------------------------------

            Insgesamt    KopiertÜbersprungenKeine Übereinstimmung    FEHLER    Extras
Verzeich.:        239        239         0         0         0         0
  Dateien:       1892       1892         0         0         0         0
    Bytes: 2968068139 2968068139         0         0         0         0
   Zeiten:    0:00:00    0:00:00                       0:00:00   0:00:00
   Beendet: Donnerstag, 29. Oktober 2020 14:20:57

I replaced all "hardcoded" texts with [\w\.]+ because the .NET regex engine matches Umlauts as well as other international characters (such as 日本語) with \w and sometimes robocopy abbreviates long words with a . (as can be seen in the above example).

An example regex to test this is: 'Übereinstimm.日本語' -match '[\w\.]+'

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I also defaulted the thred count to the processors available threads, because 16 might be a bit high for some (older) laptops.