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
I didn't understand why a static id (id='content') is set right after this comment. It seems that either the comment is wrong or the property is unnecessarily set.