* Added getBaseEdge, getClusteredEdges updateEdge and updateClusteredNode to allow option changes of the clustered edges as they are no longer the original base Edge

changing edge color is a good example.
i.e network.clustering.updateEdge(originalEdge.id, {color : '#aa0000'});
will now update all edges including the ones that were created when clustering.

Also when clicking on a clustered edge the event returns the clustered Edge id, which doesn't mean a lot.
This can be now converted back into the original edge with
network.clustering.getBaseEdge(clusteredEdge.id)

Similar with updateClusteredNode
This new method allows the options to be changed on a clustered Node.

i.e clicking on a clustered node gives its clustered node id.
Want to change the clustered image to a star then do this
 network.clustering.updateClusteredNode(clusteredNodeId, {shape : 'star'});

* Updated docs with getClusteredEdge, getBaseEdge, updateEdge and updateClusteredNode

Also added method subsections into contents

* Added better error handling to updateEdge and updateClusteredNodes

corrected errors spotted by @mojoaxel

* Added example html demonstrating getBaseEdge, getClusteredEdges updateEdge and updateClusteredNode

Added a "showLegend" option which can be used to toggle legend drawing
Added legend drawing to 11_tooltips and to playground examples
Added description of showLegend option to documentation

- Added interpolation option for interpolation of images, default true.

- Added parentCentralization option for hierarchical layout.

added example. Improved handling of options for hierarchical view.

-Keep single defaults location
-Update documentation on formatting function.

- Fixed #1528, #1278, avoided ID's being cast to string for methods that return ID's as well as storePositions casting to string.

-Draw points in bar icon if appropriate
-Introduce point icon
-Cleanups

Separate shading from line drawing (fixes drawing order)
Cleanup of draw code
Fix icon-shading CSS override

Removed some old incorrect texts.

added docs

Node labels don't currently make use of the 'align' property, so this reuses
the existing property.

The label code has a number of alignment options that make sense to edges only,
so the Edge/Node now passes a boolean to the Label ctor to explain which the label
is being rendered for

Theoretically, there are multiple node shape types that this could apply to.