Add Pig Latin

I've added a new language.  ;-)
Thanks for filling in these files, but now there are dead links at the end of these pages.  Could you remove everything below this point?  The last `.md` file the reader reaches on any path should not have options.  For example, see [this file](https://github.com/udacity/create-your-own-adventure/blob/c4f2bf7caac641df1c979a2db056a532e0c93e23/english/light-fire/fire.md) from an early version of the story.

The same thing goes for the other two files.  Sorry about all the trouble.