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/parfait/test_sol_method.rb

@@ -0,0 +1,32 @@
+require_relative "helper"
+
+module Sol
+  class TestSolMethod < MiniTest::Test
+    include SolCompile
+
+    def setup
+      Parfait.boot!(Parfait.default_test_options)
+      ruby_tree = Ruby::RubyCompiler.compile( as_main("a = 5") )
+      @clazz = ruby_tree.to_sol
+    end
+    def method
+      @clazz.body.first
+    end
+    def test_setup
+      assert_equal ClassExpression , @clazz.class
+      assert_equal Statements , @clazz.body.class
+      assert_equal MethodExpression , method.class
+    end
+    def test_class
+      assert_equal Parfait::Class , @clazz.to_parfait.class
+    end
+    def test_method
+      clazz =  @clazz.to_parfait
+      assert_equal Parfait::SolMethod , clazz.get_instance_method(:main).class
+    end
+    def test_type_method
+      clazz =  @clazz.to_parfait
+      assert_equal Parfait::CallableMethod , clazz.instance_type.get_method(:main).class
+    end
+  end
+end