Fill triangular bijector

[thomaspinder]

This pull request implements the fill triangular bijector, thus resolving #161 .

[google-cla]

Thanks for your pull request! It looks like this may be your first contribution to a Google open source project. Before we can look at your pull request, you'll need to sign a Contributor License Agreement (CLA).

View this failed invocation of the CLA check for more information.

For the most up to date status, view the checks section at the bottom of the pull request.

[thomaspinder]

Hi @franrruiz, I've signed the CLA - are you able to re-run the checks?

[franrruiz]

I just ran the checks again but it's still showing the error message: "Could not find a CLA for one or more contributors".

It looks like the issue has something to do with the fact that there are two different email addresses in the PR, and the system is asking for a signed CLA for each one. The one ending in *live.co.uk has "State: Ok", but the one ending in *lancaster.ac.uk shows "Need CLA".

I am not sure how to resolve this, but according to the FAQs there are two options:

• You can add your second email address to your CLA; or
• You can rebase your commits with the email address ending in *live.co.uk

Could you please try these options and let me know if it works?