Make Gadfly compatible with the new versions of Turing

[dfioravanti]

Would it be possible to update the version of "CoupledFields" used by Gadfly? Right now it makes it impossible to install the new versions of Turing. Here you can find the log of what happens when one tries to force install Turing@0.12 on a fresh julia install.

Thanks for this amazing package

[Mattriks]

It's been updated on Gadfly#master, so just do ]add Gadfly#master. We should do a minor release of Gadfly soon.

[dfioravanti]

Cool, thanks a lot =)