Add support for Zeus & Spring

Please bear with me, this is my 1st vim plugin contribution.

I am happy to rename stuff or improve the quality of the code following your comments.

Also happy to add some tests if it's not too much of a hassle. Some example I found googling: http://mudge.name/2012/04/18/testing-vim-plugins-on-travis-ci-with-rspec-and-vimrunner.html