Add curve edge with arrow head rendering.
Rename edges renderers files in examples.
Fixing custom edge example.
Enchance edge renderer selection.
Fix issue with incorrect node type renderer.
Fix minor typo (instanciate -> instantiate)
Change other use of "instanciate" -> "instantiate"
Added a plugin for drag nodes and modified 2 examples for see how to do it
Deleted an import from a HTML file
Fixed some imports in HTML files and an instatation of a `sigma` object
Added the declaration of a few JS objects
Fixes `gjslint.py` not found. See https://github.com/wzr1337/grunt-closure-linter/issues/8
Fixed the size check and the dragging with rotated graphs
Now the  parameter isn't needed, it can be obtained from the  on renderer's .
Merge pull request #234 from jeroencoumans/master

Fixes `gjslint.py does not exist`
Just corrected some typos
Change edge type selection mechanism to default.
Fixing edge renerers path in examples.
dev: make it easier to build for newbies by not requiring global 'grunt-cli'.
adds grunt-cli as devDependency and uses it via 'npm run build'.
Correcting some canvas renderers documentation