Move vool block compilation into constant generation

When the lambda is passed as argument, it must be moved. This triggers the generation of a corresponding parfait object (as before, and as for other constants) but now also triggers the code build. The code being the constant as it were
Also some more name fixes from renames

lib/vool/method_expression.rb

@@ -52,7 +52,7 @@ module Vool
       nodes = []
       @body.each { |node| nodes << node }
       nodes.dup.each do |node|
-        next unless node.is_a?(BlockStatement)
+        next unless node.is_a?(LambdaExpression)
         node.each {|block_scope| nodes.delete(block_scope)}
       end
       type_hash = {}