Add fullScreen plugin
Review README, Add MIT License
Update README
Merge branch 'master' into HEAD

Conflicts:
	src/utils/sigma.utils.js
Removed duplicated functions from sigma.utils.js

The functions getQuadraticControlPoint, getPointOnQuadraticCurve, getPointOnBezierCurve and getSelfLoopControlPoints were duplicated in sigma.utils.js, due to some weird git merging. I removed the oldest definition.
Refactor plugins.fullscreen
Refactor plugins.fullscreen

Merge branch 'plugin/fullscreen' into linkurious-version
Add plugin.fullScreen to Gruntfile
Merge branch 'plugin/fullscreen' into linkurious-version
minor change in settings organization
Extract colorbrewer as a sigma plugin
Merge branch 'plugin/designer' into linkurious-version
Merge branch 'master' into merge-pr-381
fine tuning in sigma.settings.js
Related to #263: Restored renderers.def as backup

In d74879... I replaced calling the "def" renderers if not renderer has been found, by using the defaultNodeType / defaultEdgeType for finding the renderer.
Since it caused too much issues with labels renderers, I restored using renderers.def as backup, if no renderer has been found with the node / edge type or the defaultNodeType / defaultEdgeType value.

Later, it will be possible to select which node / edge / label renderer to use from a function, when #368 will be fixed.
Improve plugins.dragNodes
Merge origin/master
Improve plugins.customEdgeShapes
Merge branch origin/plugins/customEdgeShapes
Fix edge hover