Everything so far

`method-list` (for adding breakpoints) isn't ready yet because `core-selector`  is buggy.
The plan is to put `method-list` and `object-tree` on the right side in separate tabs. But `paper-tabs` was  not being compliant with `vulanize`, so that's not done yet.

Requires `O.o()` to work.

Thank you
!! is too obscure. Please, change it to something else, like
 return descriptor.set ? true : false || descriptor.get ? true : false;