Fixed #55. Had to add a visit method to each of the AST node which, in many cases, just called Eval, but this was all done for Block.  Block on a visit will create and return a Block object instead of evaluating its contents. The console now calls visit instead of eval.
Formatting.
Added a Visit method to File.  Which is call Visit on each of its Exprs. This is called from console when loading a project.