My changes to Microsoft's DynamicExpression

Hi,
I've presented Microsoft work with dynamic expression parsing on previous post.
Now I'll like to present my upgrades to it: I've add both Select and SelectMany enumerable operations as well as some more Enumerable "simple" methods like First, Last and Distinct.

The Select and SelectMany are more tricky because they have dynamic nature - they do not have static parameter types and return value type so they need to be handle little different.
My addition are to the dynamic string parsing language - the library already had strong type Select method but did not support putting Select inside a string for parsing.

The code is inside a gist at http://gist.github.com/489298