Resolve #7, improve AbstractDAOFactory usage
Add verification in AbstractDAOFactory#addDAO for previous DAO

Add unit test (which requires Mockito - pom.xml updated).
Also add a DAOAdaptater in test classes.
Improve test coverage on MVC package.
Improve coverage in QueryGenerator
Fix log message
Remove MD5Error
Remove logger from Column class
Improve test coverage on ListCellTextRenderer class
Add a getConversionFactor in the TimeConverter class

Update unit tests as well.
Update use of constant for conversion in Time and TimeSec