Fixed issues in adding/removing cells where colspans remained.
Fixed issues in adding/removing cells where colspans remained.

rbevers/fitnesse,amolenaar/fitnesse,jdufner/fitnesse,rbevers/fitnesse,hansjoachim/fitnesse,hansjoachim/fitnesse,amolenaar/fitnesse,jdufner/fitnesse,amolenaar/fitnesse,rbevers/fitnesse,jdufner/fitnesse,hansjoachim/fitnesse