Merge pull request #183 from clacote/master

PlanedSlot.id sequence
Merge pull request #184 from clacote/master

Fixed enum Slot duplication in planning admin
Dynamic public planning
Expose start and end on /api/talks
Expose start and end on /api/talks/{id}
Display slot on talk details page.
Slot hours on 24H format (not am/pm)
Expose speaker's urlimage on talks?details=true
Merge pull request #185 from clacote/public-dynamic-planning

Dynamic public planning