Fix occasional collapsibleTabs JS error

vector/vector.js depends on $.fn.collapsibleTabs, but that's defined in
vector/collapsibleTabs.js which is loaded *after*. The only reason it
worked most of the time is because the invocation is wrapped in a document
ready callback. Most of the time, the document isn't ready yet when
vector.js runs, so the callback is deferred and $.fn.collapsibleTabs is
created before the callback runs. But if the document is already ready,
the callback runs immediately without $.fn.collapsibleTabs having been
created yet, and so it throws an error.

Fixed by including the .js files in the proper order.

Change-Id: If101efe82970bda7a39d827ce3c668abad6a5f5e