Add ability to create UTexture from Image http links. 

 -  Add the concept of RequestResultType (JSON & Texture) and broadcast relevant OnCompleted Event accordingly.
 -  Refactor - Remove Response UVaRestJsonObject as member variable. Only Create UVaRestJsonObject/UTexture when explicitly asked.
 - Only PNG format for now - adding more formats should be trivial. 

For Example: 
 
![image](https://cloud.githubusercontent.com/assets/4664618/4608840/a7ee0e66-528a-11e4-8b5d-04962e686c56.png)

CAVEAT: This will break existing blueprints/code.

TODO: Possibly refactor completety and decouple UVaRestRequestJSON request from result TYPE. The Request perhaps only outputs raw TArray data and other classes work on that raw data.