2 splits, not 3 in "pattern, search, replace = line.split(None, 3)"

Changed 3 to 2 in this line of code, in several places in  in 6.5, 6.6, 7.6, and in example code files. Two splits give three values. (Maybe line.split() with no args would be easier in this case?) See http://docs.python.org/3.3/library/stdtypes.html#str.split