Previously we used IScriptPosition for context (e.g. error reporting)
during parameter binding, but in some cases we want more information, so
we'll use the Ast instead.
This change just adds the Ast, it doesn't make explicit use of it.
I (Jason Shirk) ran https://github.com/dotnet/codeformatter with the default rules, basically:
codeformatter /nocopyright "/c:DEBUG,UNIX,CORECLR" @files.rsp
This caused a few problems building, which were fixed up manually.
Notable changes:
`this.` is removed unless needed to disambiguate.
private instance fields are renamed to have a `_` prefix.
private static fields are renamed to have a `s_` prefix.
I left some projects alone (like PackageManagement) and also left some generated code alone.