mobizt/Firebase-ESP8266: v3.1.12

v3.1.12 stable release

• Add Firebase.ready() function for token generation ready checking.
• Add Firebase.setSystemTime function for setting the system timestamp manually.
• Add Firebase.RTDB.setQueryIndex and removeQueryIndex functions for database query indexing.
• Add Firebase.RTDB.setReadWriteRules function for adding or removing the read and write rules in the RTDB rules.
• Add FireSense addon, the Programmable Data Logging and IO Control library.
• Improve the token handling in the examples.
• Change the ambiguous defined macro FIREBASE_HOST and FIREBASE_AUTH to FIREBASE_URL and DATABASE_SECRET.
• Remove Firebase.begin requirement from FCM.
• Fix compilation errors of conflicts between different FirebaseJson class.
• Fix the RTDB streamAvailable issue.