Version notes

For instructions on how to add version notes to any portlet, see : https://wiki.jasig.org/display/UPC/Marketplace

This pull request adds 1 file, a pojo representing a version note.

This pull request modifies the entity file to highlight this new addition and the robustness of order doesn't matter.

Version notes compressed:
![version_notes_compressed](https://f.cloud.github.com/assets/5521429/2112185/cc60b790-901a-11e3-9f83-120cbf699226.png)


version notes expanded:

![version_notes_expanded](https://f.cloud.github.com/assets/5521429/2112184/c9d0cefc-901a-11e3-9883-0afa321937f5.png)


This pull request also adds the ability for the marketplace search registry to look at version notes. IE, the search portlet will also search the content of the version notes to decide if it shows your portlet in the search results.