Minor fixes and updated documentation.
Corrected the coding of the rating-scale items of the ISSP 2000.
CAR, IND, FARM, WATER, TEMP, and GENE were coded 0 (dangerous) to 4 (not dangerous) instead of 1 (dangerous) to 5 (not dangerous).
plotworth() is defunct – use plot() (or plot.wmat) instead.
Minor fixes and improvements.