New method helpers in jDbTools to manage a database

[laurentj]

jDbTools should provide methods to create or drop tables, create/alter/drop fields, indexes, references etc..

[laurentj]

work in progress:  http://hg.jelix.org/jelix/jelix-trunk/rev/b35851acf513

[laurentj]

work in progress

•  http://hg.jelix.org/jelix/jelix-trunk/rev/b72a932c79ba
•  http://hg.jelix.org/jelix/jelix-trunk/rev/bbd424885692
•  http://hg.jelix.org/jelix/jelix-trunk/rev/9fdedb9ea8c7
•  http://hg.jelix.org/jelix/jelix-trunk/rev/50bb178734ee