renamed to GitHubAPI, merged models into main assembly, added functions for issues & issue comments

renamed because this isn't just for csharp (although it's written in it)
also wanted to limit the - in the namespace as this is very rarely seen
in .net
added VSTests alongside Nunit tests because the express products can't
use the Nunit test adapter extension (which sucks)
FYI A test project can have an App.config, which i think is a bit nicer
than the .dll.config you had people using
Merged Nunit & VSTest frameworks

used suggested approach of ifdef
added some tests for issues get, create, edit (but many are
ignored/skipped)
unable to test Nunit
set JsonObject back to dynamic access enabled after NuGet update.
removed VSTest specific project
added App.Config to ignore
Fix tests

* Update TestsSpecBase to use the change file name when it loads the .config file.
* Stopped tracking App.config so that git ignores any changes to it. We don't want people checking in their github.com account passwords and such.
* Updated .gitignore