Added a writeFormat() method to Algorithm which must be called by the
write() method of derived classes.

fixes #5643

While checking whether a match is a real match, the index of the corresponding column (row) for a row (column) is checked. The limit should be the number of the real columns (rows) for a given row (column).

- common operations moved to separate class
- debug console messages removed
- test results are stored in memory instead of file

(with this else-branch, argument contour2 would not be used at all)