Links are no longer broken and the back and forward buttons work.
Fixed comment link to dartdoc
Breadcrumb linking works
Breadcrumbs have better structure.
Added String path to Items for mapping in data.dart
Removed path through objects to each page and improved browser navigation.
Removed object path and allowed for navigation through only path string.
Cleaned up commenting and line spacing.
Added homepage back and cleaned up a few lines
Changed variable names and cleaned up logic
Breadcrumbs recognize private members
Separated out functions to change the page and fixed style
Merge branch 'dev' of https://github.com/dart-lang/dartdoc-viewer into dev