gddo-server: Handle static files properly.
gddo-server: Handle static files properly.

Add handlers for newly added Bootstrap and jQuery files. These files are
stored locally now instead of being fetched from CDN. But those static
files are not handled properly in our serve mux, causing the serve keeps
requesting them infinitely.

Change-Id: Iddc680bb889f1327ec9265fa33eff94d9fa8dec4
Reviewed-on: https://go-review.googlesource.com/23721
Reviewed-by: Andrew Gerrand <395a7d33bec8475c9b83b7d440f141bcbd994aa5@golang.org>
Reviewed-by: Alan Donovan <7069e9552f9d110b0a0f326b96f22f63fb99dfc1@google.com>

golang/gddo,golang/gddo,segmentio/gddo,segmentio/gddo,segmentio/gddo,golang/gddo,golang/gddo,segmentio/gddo