pginstaller - pginst: Check for duplicated translation strings.

Log Message:
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Check for duplicated translation strings. Also, remove a couple of duplicated strings found in the german translation.

Modified Files:
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pginst/lang:
de.xml (r1.7 -> r1.8)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pginstaller/pginst/lang/de.xml.diff?r1=1.7&r2=1.8)
pginst/util:
validatetrans.vbs (r1.2 -> r1.3)
(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/pginstaller/pginst/util/validatetrans.vbs.diff?r1=1.2&r2=1.3)