When editing an instance, instance type should be passed as parameter so know we if current object is an event or an entity

[Renaud009]

Right now, we are evaluating type based on id prefixing character, which is generally a bad practice.
This might have major impact on the main brat application tho.
We could also use the provided type and look into the collection object to figure out type (event or entity).

[reckart]

In WebAnno, we look up the type information in our internal representation of the document. If you store the document representation in the browser, you should be able to look up type information there without requiring brat to pass it to you.