changed BoardState so that everything should use negative numbers when determining whether or not a cell can be changed. the function getCellContents returns the absolute value of the cell, and isModifiable returns correctly as well. Finally setModifiableCell correctly makes negatives/positives and prints a message if a 0 is changed to negative/positive.
changed BoardState so that everything should use negative numbers when determining whether or not a cell can be changed. the function getCellContents returns the absolute value of the cell, and isModifiable returns correctly as well. Finally setModifiableCell correctly makes negatives/positives and prints a message if a 0 is changed to negative/positive.

git-svn-id: 7b60c18216eb38535f23d2b6dcb02b245ca483a0@293 361cd0e3-9505-6840-87d6-36ed75c01346

Bram28/LEGUP,Bram28/LEGUP,Bram28/LEGUP