Topogram

Bug fix :
- CSV import accept single-column file
- parse CSV errors properly

- singleton nodes keep their original color 100
- fix view title
- renaming boxes properly 60

This version fixes a few bugs and add two missing major features:
- inline editing of node and edge data - see 110
- improvements to the REST API to be consumed with the [topogram-api-client](https://github.com/topogram/topogram-api-client/) (in Python)- see 90 for details

Also added contributions guidelines in the rep.

This release contains a main changes, namely :
- interactive node/edge creation 77
- move towards ES6, npm and cleaner app structure 81
- testing and integration with travis-ci 79
- a REST API to create / update topograms from command line 90 (see the [api-client](https://github.com/topogram/topogram-api-client/)

Don't use this release, too unstable.