Merge pull request #73 from otupman/fix-back

Added some tests to demo that the approuter's back is really working.
Merge pull request #76 from otupman/development

Development
fix(app router): back across sections with articles was failing

So, section3/article3 -[back]->section2/article2 -[back]->/section1/article1 was actually *adding* to the history rather than removing things (so you would, after two backs, end up back at section3/article3)