DB.SheduleField support

[ejs-ejs]

Partial support for pickling DB.ScheduleField.

[eirannejad]

This PR seems odd. DB.ScheduleField does not have any constructors. How are you deserializeing the stored data into a DB.ScheduleField?

[ejs-ejs]

This PR seems odd. DB.ScheduleField does not have any constructors. How are you deserializeing the stored data into a DB.ScheduleField?

The deserializing is needed for numeric fields, like 'width' AFAIR . What I [think | hope], the API is creating a new DB.ScheduleField and the properties can be applied to the existing DB.ScheduleField. I need to clean the kind-of-working code, the repo is https://github.com/ejs-ejs/py-ejs.

[jmcouffin]

@ejs-ejs did you get the chance to validate this change and test it?

[jmcouffin]

I will leave it alive for an extra week then close the PR