Update sigma.parsers.gexf.js

Need to do : 
obj.y = - obj.viz.position.y; 

Otherwise the graph is up side down compared to what you had in gephi. Can be annoying for map for example.
Add timeout for Firefox to dragNodes plugin.  Closes #278.
Fix for overlapping nodes not being draggable
Fix case where initial node isn't considered current when it hasn't been left after entering/exiting an overlapping node
Remove check for over/outNode occurring multiple times. Unnecessary.
Fix comments
Better variable name for array of hovered nodes
Rework of hover logic to allow a single label to be displayed
Add self referenced nodes edge rendering.
Fixed buggy drag behaviour when container is offset.

If _container is offset from the top-left corner of the page, it is very easy for local/global mouse position errors to creep into calculations. In particular, when dragging a node it hovers a fixed distance away from the mouse. This more robust calculation fixes these issues (including padding which is independent of the bounding rect), and allows the container to be placed anywhere with any offset/margin/padding, and it need not be position: absolute.
added HITS statistics computation /jacomyal/sigma.js#309
removed call to , not needed in this plugin
Fix #346 - FA2 supervisor is now relative to a sigma instance
Adding an option to disable webworkers for FA2 layout
It is now possible to shunt the worker by specifying worker: false in FA2 configuration.
Adding possibility to run FA2 from external worker file
Fix #347 - adding a polymorphism for the autoRescale setting
It is now possible to pass an array of properties to rescale to the autoRescale setting.
Temporary dirty tricks to permit usage of sigma in node
fixes build for the forceAtlas2 plugin.
Merge pull request #348 from luca/master

fixes build for the forceAtlas2 plugin
Update basic.html

suggesting to fix spelling from instanciate to "instantiate", and instantiation to "instance".
More occurances across project, not fixed yet.