Fix notificationbox orientation and add splitter to resize panel

If you change the environment to *Browser* from menu, the notificationbox is shown on the left side instead of on top.

![live-scratchpad-before](https://f.cloud.github.com/assets/42596/120320/34266822-6cd9-11e2-9ae2-5e200092af48.png)

This patch fixes it.

![live-scratchpad-after](https://f.cloud.github.com/assets/42596/120324/68253a9a-6cd9-11e2-83ed-8a9dc3818fe6.png)

The problem is Live Scratchpad iframe is now shown on the left.
:open_mouth: