Update yury.kovalyov.pl

In accordance to a convention - we have to print not a path but entry point,
e.g. 
instead of -
* printe "No sush entry point! Check test file data, please.\n";
should be -
print "$head\n";
Update yury.kovalyov.pl

The only difference is an extra "\n" for "10_no_exit.dat".
Reference code handles "10_no_exit.dat" specific situation *artificially* -
* print "\n" if !$IS_INTERACTIVE_MODE;
Seems we have to do the same "\n" output for batch (e.g. non-interactive) mode.
Update yury.kovalyov.pl

00_example.dat -
1) Need to fix extra "''"- to be aligned with updated code of referenced solution

01_large_linked_list.dat -
2) Need to add ";" as data expected to be evaluatable
Update yury.kovalyov.pl

1) In acordance to the original task we expected to get an extra space (exactly one!) after "--" - need to fix several samples (06_delete_join.dat + 08_select_join.dat) that contain no spaces for "--end" statements or apply this fix to allow correct processing of deviated examples. Logic of program was not changed.

2) Seems like referenced solution uses '' for NULL values from database - thus aligning our output with.
Update yury.kovalyov.pl

git hub corrupts example. removing example for safety.
Merge pull request #25 from student-perl/master

yury kovalyov's 03 05 07 09 appeal++ for 1..4