Includes option to convert all enrolments to enrol_manual instances, support for mapping of custom fields and fixes for several other problems. This does not include support for custom enrol tables, it will be addressed in another issue.
Some early steps in restore are using capability checks to decide how to
restore some information. But at that stage, if the course contents have
been removed and the user had perms at course level only (usually teacher)
the process can fail because some content is not restoreable due to the
lack of permissions.
Moving the restorer step to the beginning really helps is those situations
and it does not hurt at all.
Also, fixed one notice detected when testing this.
* Root settings are now check boxes rather than selects
* Language strings adjusted as requested
* Final continue on backup now redirecteds to restore pre ui
