Merge pull request #6 from OndraZizka/master

TODOs, comments, typos, path handling, some refactoring.
Merge pull request #7 from OndraZizka/master

TODOs, comments, typos, path handling, some refactoring. 2nd round.
Merge pull request #8 from OndraZizka/master

TODOs, comments, typos, path handling, some refactoring. 3rd round.
Merge pull request #9 from OndraZizka/master

MIGR-31, MIGR-23, work in progress. TODO: Implement createActions() in IMigrator's.