Add richer auto-complete for use in an expression evaluator. (#2962)
* Add support to auto-complete to support an expression evaluator.
* 'accentColor' is deprecated and shouldn't be used. Use colorScheme.secondary instead
* Fixed MockLoggingController.
* Fix keyCodes to work in all platforms.
* Fixed auto-complete when caret not at EOL.
* Added tests to check editing with caret inside of text (not at EOL).
* Removed expression evaluator sample.
* Only show example screen if in debug/profile and debugEnableSampleScreen is true.