Expression Tree API Futures

This repo contains various suggested expression tree improvements for System.Linq.Expressions, including:

• Microsoft.CSharp.Expressions with C# specific expression nodes for language constructs added after C# 3.0 (see CSharpExpressions)
• Fixes to work around some of the existing limitations in the expression compiler, e.g. for TryFault (see ExceptionHandlerLowering)
• An example for a proposed expression types language feature which enables other types to be used as expression trees (see ExpressionLikeTypes).
• Tools to manipulate expression trees. These were shipped as part of Reaqtive in the Nuqleon libraries.