Merge pull request #13 from mershack/master

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Merge pull request #14 from mershack/master

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Merge pull request #15 from mershack/master

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#8

D3Viewer and viewer factory added. d3viewer.html is also added. Whenever D3 viewer is launched, its launched in d3viewer.html
#8

D3 implementation added. 

1. In the D3Viewer the update data invokes the JSON structure
2. JSON lib is added
3. in the callback at d3-helper creates the d3 implementation.
#8

D3 integration implemented.

Developers' guide:

1. Create a viewer extending Abstract class D3Viewer which need implementing updateData method
2. Create a viewerFactory for the D3Viewer with a creatorType preferable with no space. 
3. In The VizOnlineServlet register the viewerFactory. 
4. In the web , d3/JSClient create a jS named with Creator type with structure:
function JSD3Client()
{ 
};

JSD3Client.prototype.dataUpdated = function (data, canvas, canvasWidth, canvasHeight)
{
...
}

5. The D3 viewer will automatically call the dataUpdated method. Where developers can work with d3 implementation.
#8

GraphD3Viewer.java is added
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