Fix broken anchors

refer to issue #68
https://github.com/GoogleChrome/devtools-docs/issues/68
Merge pull request #70 from wonglok/master

Fix broken anchors
Merge github.com:GoogleChrome/devtools-docs into shortcuts-updates

* github.com:GoogleChrome/devtools-docs:
  Fix broken anchors
added expand/collapse node and all its children shortcut