Resync: merge of dkomanov/master into junit
Renamed the package for new task.
Restructured the project to match the required hierarchy.
Check whether db format is valid.
Some implementation.
Core transaction functionality.
Unit testing.
Proper storing of changes.
Proper access levels.
Random fixes.
Major overhaul of file I/O.
Random fixes.
Final changes.
Refactoring and some fixes backported from 05-Structured.
Different expect syntax to stop Travis from complaining.
Final fix: accidentally replaced expect with different exception.
Attempt to fix merge conflict.
Check for empty argument.
Merge pull request #311 from Norrius/junit

Захаров Андрей, 395, JUnit