Cleaning up some code, fixing paths, other things

For all intents and purposes, the classes in GitHub.Api and GitHub.Unity live on the same namespace, they see each other's internals and are only separated because some need threading APIs while others need access to Unity APIs. This consolidates everyone into a GitHub.Unity namespace so it's easy to move things between projects.

Also handle paths with NPath 'cause slashes

Merge pull request #140 from github/fixes/header

Install Support

Make NPath a bit more resilient to not having an environment

Also add some handy implicit casts for strings

Some fixes to the history view

Fixing format order of ConsoleLogAdapter

Make pull work properly