Support for user specified projection in vector plot function

[thomascrocker]

The vector plot function by default plotted data on the same projection as the source data.

For the purposes of comparing RCMs and GCMs it is desirable to be able to manually specify the projection, so that all models are compared on the same projection.

I have implemented this functionality in a branch, as well as a couple of other bug fixes to the function. However, when I tried to push my branch to the repo I got a message saying I didn't have permission to do so..

[nhsavage]

can you please do a Pull Request for this and we can review it? we may need you to add some unit tests as well

[thomascrocker]

can you please do a Pull Request for this and we can review it? we may need you to add some unit tests as well

I can't create a pull request because Github won't let me push the branch I have created locally to the repo. So there is no way to associate the pull request with my changes.

git push -u upstream vector_plot_fixes
remote: Permission to MetOffice/CATNIP.git denied to thomascrocker.
fatal: unable to access 'https://github.com/MetOffice/CATNIP.git/': The requested URL returned error: 403