This commit adds the changes in questiontype base
to work with new question tables and the new structure in the
databse. Also needed for versioning.
This implementation will also introduct the question status
which allows a question to be in draft and ready status.
I also introduces changes to the base view where it shows
the latest version of the questions. The view of versions
for a question is not implemented in this commit.
This implementation will also introduce changes in the core
qtype plugins to support versioning and the changed
db schema.
This implementation will introduce a qbank plugin "editquestion"
which will implement the edit question, add question and copy
question actions in the question bank view by replacing the
core classes. Having this plugin will give users the
flexibility of enabling or disabling these actions.
