Move off fake-cli

[TheAngryByrd]

Proposed Changes

This moves the build scripts away from using fake-cli and using a dotnet project to run it. fake-cli hasn't been updated in quite a long time and isn't using the latest version of FSharp.Compiler.Services so tooling like Ionide work with it anymore.

There aren't major changes to the build script other than configuring it to run in just a dotnet process. The big differences are:

• needing to set the execution context to allow FAKE to run as normal.
• Since the execution context is now created in main rather than by the FAKE script knowing it via fake-cli, anything that uses the context needs to be initialized after we set the context.

These should help anyone looking to migrate their code to use a dotnet project.

Summary

• This moves build.fsx to a .fsproj under ./build/ which is largely similar.
• Updates FAKE packages off the alpha version to the release
• Updates paket tool off beta to release version

Deals with #231 a bit

Types of changes

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• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

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• Build and tests pass locally
• I have added tests that prove my fix is effective or that my feature works (if appropriate)
• I have added necessary documentation (if appropriate)

Further comments

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