Rename Vool to Sol

Simple is really the descriptive name for the layer
Sure, it is "virtual" but that is not as important as the fact that it is simple (or simplified)
Also objct (based really) is better, since orientated implies it is a little like that, but only orientated, not really it. Sol only has objects, nothing else
Just cause i was renaming anyway

test/ruby/test_class_method_statement.rb

@@ -40,35 +40,35 @@ module Ruby
 
     def setup()
       input = "def self.tryout(arg1, arg2) ; a = arg1 ; end "
-      @lst = compile( input ).to_vool
+      @lst = compile( input ).to_sol
     end
     def test_method
-      assert_equal Vool::ClassMethodExpression , @lst.class
+      assert_equal Sol::ClassMethodExpression , @lst.class
     end
     def test_method_args
       assert_equal [:arg1, :arg2] , @lst.args
     end
     def test_body_is_scope_zero_statement
-      assert_equal Vool::Statements , @lst.body.class
+      assert_equal Sol::Statements , @lst.body.class
     end
     def test_body_is_scope_zero_statement
-      assert_equal Vool::LocalAssignment , @lst.body.first.class
+      assert_equal Sol::LocalAssignment , @lst.body.first.class
     end
   end
   class TestClassMethodStatementImplicitReturn < MiniTest::Test
     include RubyTests
     def setup()
       input = "def self.tryout(arg1, arg2) ; arg1 ; end "
-      @lst = compile( input ).to_vool
+      @lst = compile( input ).to_sol
     end
     def test_method
-      assert_equal Vool::ClassMethodExpression , @lst.class
+      assert_equal Sol::ClassMethodExpression , @lst.class
     end
     def test_method_args
       assert_equal [:arg1, :arg2] , @lst.args
     end
     def test_body_is_scope_zero_statement
-      assert_equal Vool::ReturnStatement , @lst.body.class
+      assert_equal Sol::ReturnStatement , @lst.body.class
     end
   end
   class TestClassMethodStatement < MiniTest::Test