Facelift for Value Classifications

A redo of the Value Classification UIs.

* Refactor and push up a lot of code to PnlAbstractTableAnalysis in order to ensure consistency between Value and Interval Classification UIs. This also removes a lot of redundancy.
* Replace "Unit of measure" with more specific labels, such as "Line width unit" and "Symbol size unit".
* Add javadoc to clarify the correspondence between classes and analyses (when I first started working on this code, it wasn't immediately obvious to me that PnlRecodedPoint corresponded to Value Classification - Point and PnlCategorizedPoint corresponded to Interval Classification - Point).

See #475.

#### Before
![old_vcp](https://f.cloud.github.com/assets/2470768/810817/71d46e2a-eec1-11e2-9119-fb0688b73031.png)
![old_vcl](https://f.cloud.github.com/assets/2470768/810818/760ae2a8-eec1-11e2-8c15-542d0bce899f.png)
![old_vca](https://f.cloud.github.com/assets/2470768/810820/785cde12-eec1-11e2-9d06-ea054539a63f.png)

#### After
![new_vcp](https://f.cloud.github.com/assets/2470768/810823/7b90e628-eec1-11e2-83ba-20e98a955712.png)
![new_vcl](https://f.cloud.github.com/assets/2470768/810825/7df2acda-eec1-11e2-8917-b1d0bf633051.png)
![new_vca](https://f.cloud.github.com/assets/2470768/810827/7fff1c20-eec1-11e2-8bfe-4b274cc773e7.png)