Ability to set and retrieve meta data

Description

It is now possible to add meta data properties, retrieve or set set meta data values for project items (bins, clips).

• A new PremiereProject.add_meta_data_property was added allowing to define additional meta data properties for all items in a project.
• New get_meta_data and set_meta_data methods can be used to retrieve and set meta data properly values.

For example:

project = engine.current_project
project.add_meta_data_property("myproperty", "My Property", float)
mybin = project.get_bin_by_name("mybin")
val = mybin.set_meta_data("myproperty", 30.0)
val = mybin.get_meta_data("myproperty")

Note: Limitations in the Adobe Premiere API can cause unexpected behaviours. For example it is not possible to check at the moment if a property is already defined in the project meta data schema, so adding a property which already exists will have no effect.

What's Changed

• 11730 meta data by @gplsteph in #8

Full Changelog: v1.3.0...v1.3.1