couple new features for string wrapper

tests/StringTest.cpp

@@ -86,4 +86,47 @@ TEST_CASE("String")
 		REQUIRE(str2 == "World");
 		REQUIRE(str2 != "Hello");
 	}
+
+	SECTION("Trim")
+	{
+		String str1("  Hello World  ");
+		REQUIRE(str1.Trim() == "Hello World");
+	}
+
+	SECTION("FindIndex")
+	{
+		String str1("Georg will save us all from our doom");
+		REQUIRE(str1.FindStartIndexOf("save") == 11);
+	}
+
+	SECTION("Upper/Lower")
+	{
+		String str1("Hello World");
+		str1.ToUpper();
+		REQUIRE(str1 == "HELLO WORLD");
+
+		String str2("Hello World");
+		str2.ToLower();
+		REQUIRE(str2 == "hello world");
+
+		String str3("Georg will save us all from our doom");
+		str3.ToUpperStarters();
+		REQUIRE(str3 == "Georg Will Save Us All From Our Doom");
+	}
+
+	SECTION("Substring")
+	{
+		String str1("Hello World");
+		REQUIRE(str1.Substring(0, 5) == "Hello");
+		REQUIRE(str1.Substring(6, 11) == "World");
+	}
+
+	SECTION("FromString")
+	{
+		String str1("42");
+		REQUIRE(str1.FromString<int>() == 42);
+
+		String str2("42.42");
+		REQUIRE(str2.FromString<float>() == 42.42f);
+	}
 }