Maintenance + Test fixes + DemoApp in Kotlin

[FIX] DomainPinningPolicyTest.testBadPolicyTld() was not working anymore because of the new behavior of the HostnameValidator
[FIX] BackgroundReporterTest.testPinValidationFailed() was not working correctly and could triggered failure
[FIX] Change Android version number check in TrustKit
[MAINTENANCE] Update version number dependencies
[FEATURE] Add new demo app in Kotlin

datatheorem / TrustKit-Android