Reorganized API

https://www.youtube.com/watch?v=-W6as8oVcuM

We have reorganized Plottable's API and module system to be better organized from the perspective of an API consumer. It will also scale better as the library grows.
However, every single use of Plottable anywhere is now broken. Sorry!

The new module system is as outlined below. (Before, all classes and submodules were attached to the top-level Plottable module.)

Plottable
  - Abstract
    * Axis
    * BarPlot
    * Broadcaster
    * Component
    * ComponentContainer
    * Interaction
    * Plot
    * PlottableObject
    * QuantitiveScale
    * Scale
    * XYPlot

  - Axis
    * Category
    * XAxis (to be deprecated)
    * YAxis (to be deprecated)
    * Axis  (to be deprecated)

  - Component
    * AxisLabel
    * Gridlines
    * Group
    * Legend
    * Table
    * TitleLabel
    * ToggleLegend

  * DataSource

  - Interaction
    * Click
    * Drag
    * DragBox
    * Key
    * Mousemove
    * PanZoom
    * XDragBox
    * XYDragBox

  - Plot
    * Area
    * VerticalBar 
    * Grid
    * HorizontalBar
    * Line
    * Scatter

  - Scale
    * Color
    * InterpolatedColor
    * Linear
    * Log
    * Ordinal
    * Time

  - Singleton
    * KeyEventListener
    * RenderController

  - Template
    * StandardChart

  - Util
    - Axis
    - DOM
    * IDCounter
    - Methods
    - OpenSource
    * ScaleDomainCoordinator
    * StrictEqualityAssociativeArray
    - Text
    - WordWrap