Added
=====
- add formatter \'black\'
- Slots filled before the start of a form are now validated upon form start
- In debug mode, the values of required slots for a form are now printed
before submitting
Changed
=======
- [validate](){} functions for slots now return dictionaries of form {slot: value}
instead of value
Fixed
=====
- Slots extracted from entities in user input upon calling form activation are
now correctly validated