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_statement.rb

@@ -1,24 +1,24 @@
 require_relative "helper"
 
 module Ruby
-  class TestClassStatementVool < MiniTest::Test
+  class TestClassStatementSol < MiniTest::Test
     include RubyTests
 
     def setup
       input = "class Tryout < Base;def meth; a = 5 ;end; end"
-      @vool = compile( input ).to_vool
+      @sol = compile( input ).to_sol
     end
     def test_class
-      assert_equal Vool::ClassExpression , @vool.class
+      assert_equal Sol::ClassExpression , @sol.class
     end
     def test_body
-      assert_equal Vool::Statements , @vool.body.class
+      assert_equal Sol::Statements , @sol.body.class
     end
     def test_compile_class_name
-      assert_equal :Tryout , @vool.name
+      assert_equal :Tryout , @sol.name
     end
     def test_compile_class_super
-      assert_equal :Base , @vool.super_class_name
+      assert_equal :Base , @sol.super_class_name
     end
 
   end
@@ -63,15 +63,15 @@ module Ruby
 
     def test_if
       input = "class Tryout < Base;  false if(true) ; end"
-      assert_raises_muted { compile( input ).to_vool}
+      assert_raises_muted { compile( input ).to_sol}
     end
     def test_instance
       input = "class Tryout < Base;  @var = 5 ; end"
-      assert_raises_muted { compile( input ).to_vool}
+      assert_raises_muted { compile( input ).to_sol}
     end
     def test_wrong_send
       input = "class Tryout < Base;  hi() ; end"
-      assert_raises_muted { compile( input ).to_vool}
+      assert_raises_muted { compile( input ).to_sol}
     end
   end
 end