Added the Yak plugin to the example-plugins.

Note also added pom to the exmaple-plugins to enable exmaples to build
with the other modules. The Yak plugin follows the XLD Customisation
Manual.

Build changes for Yak Plugin

Modifed POM to be in line with the rest of the community-plugin
project. Also added README.

Also include a standalone POM if people want that for their own plugins

Update README.md

Fixed formatting issue

Added documentation in comments to code

Also some refactoring.

Added documentation in comments to code

Also some refactoring.

Typo fix
Merge branch 'master' of https://github.com/tombatchelor/community-plugins

Conflicts:
	README.md