GPIOChip VALUE only allows 15 Character long Strings

[mayrthom]

When I use the GPIOChip FB and the "VALUE" input string has more the 15 characters the IO handle gets screwed up.

In my application "TestApp" for example:
Name of IX FB: "DI_Sensor1"
VALUE of GPIOChip "TestApp.DI_Sensor1"

Console Output:

DEBUG: T#1769001696107620302: [IOMapper] Register handle ▒▒
DEBUG: T#1769001696107908709: [IOMapper] Register observer TestApp.DI_Sensor1

With less then 15 Characters it works flawlessly.

[gravemalte]

I inspected this and this is because of the use of WSTRING in the GPIOChip FB. The WSTRING is a bit weird and will produce garbage. This fix will go hand in hand with #759

[azoitl]

If possible I would be happy if you could do the WSTRING to STRING fix in an own PR. I fear that putting all into on Pr for #759 will otherwise get rather big and cluttered.