Android SDK 5.1.0

Changelog

• added : interstitial feature
• added : online sdk configuration access
• added : headers access from ws request sucess callback
• added : PATCH device call with push data
• fixed : sdk restart on application resume
• fixed : ws request accept-charset header
• fixed : firebase crash reporting
• fixed : add json param to request
• fixed : ws request header param encoding
• fixed : remove slash after ws sdk url
• fixed : linter issues
• changed : update dependencies
• changed : clean code