[Fix #1374] Always auto-correct one cop at a time

The only way to guarantee that two cops don't destroy
the code by doing simultaneous changes, is to save
the file after letting one cop to its corrections, and
then parse it again before doing any more corrections.
Merge pull request #1379 from jonas054/1374_autocorrect_problem

[Fix #1374] Always auto-correct one cop at a time