Add support for simple empty StringView.

tests/StringViewTests.cpp

@@ -76,4 +76,9 @@ TEST_CASE("Out of scope char* doesn't lose reference", "[Utilities]") {
     REQUIRE(strcmp(val.c_str(), "foobar") == 0);
 }
 
+TEST_CASE("Get Empty String", "[Utilities]") {
+    REQUIRE(ArbUt::StringView::Empty() == ""_cnc);
+}
+
+
 #endif