Feat: Allow Custom Text Class and Sprites for Items

[bbazukun123]

• A custom textClass can be passed in, eg. you can use I18nLabel or your own Text wrapper class.
• A textUpdate function can also be passed alongside to handle texts that won't update view textView.text.
• Add the ability to pass texture aliases or instances to populate the dropdown.
• You now have to explicitly specify which type of content is supported for the dropdown via the new type parameter, which will prompt other relevant options .
• Remove unused scrollbox options.
• Add example for the use of sprite items.

[Zyie]

closing this for the simpler implementation in #144