Sparql: update editor

[julienmachon]

We need to start using Yasgui, which seems to be what everyone is using: https://github.com/TriplyDB/YASGUI

It has syntax check, multiple tabs, different visualisation (including google charts).

It's great

[samuel-kerrien]

Yes indeed, Francois has told us many times but I think it wasn't straight forward to integrate at least las time I heard. Definitely worth looking into it again !