Android and iOS native SDK update

Changed

• Android native SDK is updated to v. 5.1.2
• iOS native SDK is updated to v. 3.0.1
• Podspecs now include Beacon as dependency

Typescript and Android fixes

Fixed

• Removed the use of jcenter for Android

Changed

• Android native SDK is updated to v. 4.1.0

Added

• Typescript support

Added `navigate` API method

Added

• Added navigate API method, by @martinpoulsen (see #8)

Android SDK Upgrade to version 2.3.1

Added

• Allow HelpscoutBeacon.open to be called in basic mode (non secure mode), i.e. without encrypted signature, by @andrekovac (see #6)

Changed

• Android: Upgrade HelpScout Beacon SDK to version 2.3.1, by @andrekovac (see #6)