This patch allows the much requested selection of individual instances of modules within a course to backup and restore.
It needs A LOT of testing and probably some prettyifying too.
Complete refactoring of the system that was really awful (my fault!).
Now everything is in its place and working like a charm, making things really
easier to be implemented and amplied. Bug 3678
(http://moodle.org/bugs/bug.php?op=show&bugid=3678)
(http://moodle.org/mod/forum/discuss.php?d=26530)
Note: Everything is merged from stable but the quiz module because it has
other changes not merged for now. I've skyped a message to Gustav about it.
Merged from MOODLE_15_STABLE
in backup and restore procedure.
Added some special checks to mantain backwards compatibility
whith pre-1.4 backup files, because the meaning of some settings
has changed just now. (I've applied the same differences executed
in the upgrade process). :-)
