Add is*() functions for more types.

Test: compiles
Change-Id: Ibeba6c814ac17192481935a067b7c835c4008dc7
diff --git a/ScalarType.cpp b/ScalarType.cpp
index a60215a..fccebd6 100644
--- a/ScalarType.cpp
+++ b/ScalarType.cpp
@@ -37,6 +37,10 @@
     // do nothing
 }
 
+bool ScalarType::isScalar() const {
+    return true;
+}
+
 std::string ScalarType::typeName() const {
     return getCppStackType();
 }