* generate individual css files; fixes#1969
* simplified css bundleing
* add new generated dist-css files
* use chart specific css files in the examples
- Revamped the options system. You can globally set options (network.setOptions) to update
settings of nodes and edges that have not been specifically defined by the individual nodes and edges.
- Disabled inheritColor when color information is set on an edge.
- Tweaked examples.
- Removed the global length property for edges. The edgelength is part of the physics system. Therefore, you have to change
the springLength of the physics system to change the edge length. Individual edge lengths can still be defined.
- Removed global edge length definition form examples.