Port codebase from Python 2 to Python 3

Replace Python 2-only constructs throughout libs/: print statements,
ConfigParser -> configparser, sets.Set -> builtin set, string.split ->
str.split, xrange -> range, dict.has_key()/.iteritems() -> in/.items(),
old-style raise Exception, "msg" syntax, and __cmp__ -> __eq__/__lt__
via functools.total_ordering (Python 3 dropped cmp()/__cmp__, which
max()/.sort() rely on). Also cleaned up mixed tab/space indentation
that Python 3's stricter tokenizer rejects.

Fixed two latent bugs that only surfaced once end-to-end runs were
possible under Python 3's stricter error handling:
- HandleBestellung() compared G.Anzahl (a bound method) to an int
  instead of calling G.Anzahl() - silently "worked" under Python 2's
  permissive cross-type ordering, raises TypeError under Python 3.
- LeuteAllein() raised KeyError for VIP-group members, who are never
  added to the regular Gruppen container; now skips people with no
  group entry instead of crashing.

Verified end-to-end: bin/platz.sh --indir work/test1 and --indir
work/test2 (VIP group included) both run to completion and produce
correctly formatted output.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

libs/platz.py

@@ -11,7 +11,7 @@ __license__ = "Python"
 
 from ga import *
 from Strukturdaten import *
-import ConfigParser
+import configparser
 import optparse
 
 
@@ -33,7 +33,7 @@ if __name__ == '__main__':
 		parser.error( "--indir '%s' ist kein Verzeichnis" % InDir )
 
 	# lade Vorgaben fuer Optimierungszyklus und
-	config = ConfigParser.ConfigParser()
+	config = configparser.ConfigParser()
 	ConfigPath= os.path.join( os.getenv('PLATZ_CFG'), 'platz.cfg')
 	config.read( os.path.expandvars( ConfigPath ))
 
@@ -55,26 +55,26 @@ if __name__ == '__main__':
 
 	Z = Zyklus()
 	Z.laden( Zyklusconfig, Zyklusart )
-	print Z
+	print(Z)
 	SL = Strafliste()
 	SL.laden( Strafenconfig )
-	print SL
+	print(SL)
 	TE = Tische()
 	TE.laden( Tischconfig )
-	print TE
+	print(TE)
 
 	InputFile = XMLConfig()
 	[ PN, GN, VIPGruppe, VIPListePT ] = InputFile.laden( Bestellung )
-	print PN
-	print GN
-	print VIPGruppe
-	print VIPListePT
+	print(PN)
+	print(GN)
+	print(VIPGruppe)
+	print(VIPListePT)
 
-	print "\n-- Erzeuge Farm:"
+	print("\n-- Erzeuge Farm:")
 	F1 = Farm( Z, Sitzplatzverteilung, Tische=TE, Gruppen=GN, Strafen=SL, VIPListe=VIPListePT, VIPs=VIPGruppe )
-	#print F1
+	#print(F1)
 	S = F1.Bester()
-	print S
+	print(S)
 	S.speichern( AusgabeTP, AusgabePT )
 
 else: