[bug] Bug fixed : Incorrect behavior in API level 24-27 (Android 7.0 …

…- 8.1) akexorcist#30 akexorcist#37

[bug] Bug fixed : setDefaultLanguage does not work properly akexorcist#28
Migrate to AndroidX and latest Gradle
Migrate to Kotlin
Add UI automated test in example code
Move set default language to Application class (Please see the migrate instruction)
Add pre-implemented application class for LocalizationApplicationDelegate