Changeable timeline position

## Overview

Changealbe each timeline's position by clicking left/right arrow on timeline header.

![atmosphere-change-timeline-position](https://f.cloud.github.com/assets/2914192/1798492/688b42cc-6b52-11e3-9ad4-c90fe88c0ff1.png)

## Remarks

* The timeline definitions are stored in **Local Storage** by `AtmosSettings.Timeline.timelineDefinitions`
* The timeline's position are stored in **Local Storage** by `AtmosSettings.Timeline.timelineOrder`
* `atmos._timelineRootIds` is used for limits which timeline is enabled. e.g. **starter** branch uses only **Global Timeline**, **Talk Timeline**, and **Private Timeline**, so this property will be set three `timelineRootId`s.

## Hope

* I want to change the position of each timeline by **Drag and Drop**
* some animation is needed when the timeline's position was changed