Add FULL_BUILD_VERSION

Fix the git_commit_hashes hook, so the pre-release number is added to `AssemblyInformationalVersion`, not the `AssemblyVersion`.


:mag: @lukesmith 
Sounds good @gshutler! 
![image](https://cloud.githubusercontent.com/assets/119081/5487578/efdcfb02-86aa-11e4-9d96-1c4685b6a3fa.png)