Support schedules that don't have performance columns
Presentation and technical schedule columns are not used

These should have been removed when the sched_subjective table was
created.

task 34: Support non-fll schedules 
http://github.com/jpschewe/fll-sw/issues/issue/34
Only migrate subjective times over if they exist

If upgrading from database version 0 or 1 to 6, then the columns for
subjective times won't be in the database.

task 34: Support non-fll schedules 
http://github.com/jpschewe/fll-sw/issues/issue/34
Support no performance rounds in the general schedule

task 34: Support non-fll schedules 
http://github.com/jpschewe/fll-sw/issues/issue/34
Merge remote-tracking branch 'origin/ticket.34.support-no-performance-in-schedule'
Update changes