* Fix deploy conditions in CI script

The deploy conditions had been using a powershell-only variable, and not a environment variable. This meant that the deployment failed on both Windows and Linux (expected only on Linux).

* Remove an extra newline

* Remove Debug statements from appveyor build script

* Target Ubuntu in Appveyor CI build

AppVeyor has released support for targetting Ubuntu 18.04 environments.
This adds Ubuntu to the list of build images for Appveyor to use.

* Set clone folder to use appveyor defaults

* Check if appveyor provides appveyor-retry by trying to run it

* Minor syntax change

* Minor syntax change

* Skip using appveyor-retry (for now)

* Use forward slash for paths so that it works on both windows and linux

* Implement replacement for appveyor-retry

* Script cleanup

* Remove commented out line

* Only package releases on Windows

* Add the isWindows condition to the deploy stage

* Start on API analyzers

* Finish GuildAccessAnalyzer

* Update build script (will this do?)

* Correct slashes

* Extrapolate DerivesFromModuleBase() to an extension method

* Quick refactoring

* Add doc file