Modernize the example demo app

[JaNd3r]

• Throw in some autolayout, move view when keyboard appears...
• Add an autocomplete example.
• Provide examples for all validation types (text, integer, pattern).
  • Example for text
  • Example for integer
  • Example for pattern

[akshitverma]

Is this project still being maintained?

[JaNd3r]

Well, it's hard for me to say 'yes' if the issue to modernize the demo app is dated back to 2016. ;)

If you want to contribute an updated version, feel free to add a pull request and I will merge it.