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/sol/test_if_simple.rb

@@ -0,0 +1,30 @@
+
+require_relative "helper"
+
+module Sol
+  class TestSimpleIfSlotMachine < MiniTest::Test
+    include SolCompile
+
+    def setup
+      @compiler = compile_main( "if(@a) ; @a = 5 ; else; @a = 6 ; end;return")
+      @ins = @compiler.slot_instructions.next
+    end
+
+    def test_condition_compiles_to_check
+      assert_equal TruthCheck , @ins.class , @ins
+    end
+    def test_condition_is_slot
+      assert_equal SlotDefinition , @ins.condition.class , @ins
+    end
+    def test_label_after_check
+      assert_equal Label , @ins.next.class , @ins
+    end
+    def test_label_last
+      assert_equal Label , @ins.last.class , @ins
+    end
+    def test_array
+      check_array [TruthCheck, Label, SlotLoad, Jump, Label ,
+                    SlotLoad, Label, SlotLoad, ReturnJump,Label, ReturnSequence, Label], @ins
+    end
+  end
+end