Implemented scopes

tests/integrations/test_scopes.toy

@@ -0,0 +1,19 @@
+//shadowing
+var answer = 42;
+print answer; //42
+{
+	    var answer = 7;
+		    print answer; //7
+}
+print answer; //42
+
+//rebinding
+var question = 42;
+print question; //42
+{
+	    var question = question;
+		    print question; //42
+}
+print question; //42
+
+//TODO: scope test case

tests/integrations/test_variables.toy

@@ -7,15 +7,13 @@ var empty;
 //assign a previously existing variable
 answer = 6 * 9;
 
+//access a variable
 answer = answer + 1;
 
+//compound assignments
 answer += 5;
-
 answer -= 5;
-
 answer *= 9;
-
 answer /= 2;
-
 answer %= 10;