Code Review: Contexts3

tfpt review “/shelveset:Contexts3;REDMOND\tomat”

Contains the changes from previously reviewed shelveset IDO2 + following
changes (I needed to merge these due to TFS shutdown):

DLR, Python changes:
Replaces CodeContext by LanguageContext in BinderOps.GetDelegate and
related code.

Ruby changes:
Removes almost all uses of CodeContext from Ruby.
Adds HasScope flag to RubyCallAction which determines whether the site
takes RubyScope or RubyContext. CodeContext is not supported any more.