corrected interpretation of x-y-axes

Added the following corrections:
1) L78: the contour() function always interprets the rows of z as x-values (see R help). Hence, the for-loop must fill rows, not columns.  
2) L87: in the "red area plot" x and y were mixed up
3) L80: by adding explicit x and y to the contour()-statement, the axes are correctly labeled if limits are >0 and/or <1
4) L85: in line 85 an old German variable name was present.