Providing Unicode anchors/aliases (and using the example directories)

[peterkmurphy]

This pull request is supplied for two reasons:

1. The primary reason for the patch is as a solution for #132 .
2. To test this, I decided to use the "examples" directory (which seemed to be doing nothing). I wrote a file "read-examples.c" which basically read all the files in that directory, and threw an error if there was a problem parsing. One of the files provided is "aliasunicode.yaml" which contains a lot of smiley anchors.

All feedback is appreciated. My C is a bit rusty, and my tests may need more coverage. But hopefully things are good to merge.