Update VoIP SIP SDK for Android

Please download our latest update of VoIP SIP SDK for Android.

Change log:

– Fixed possible crash in timer implementation;
– Fixed sending ACK to server;
– Added ability to set REGISTER headers;
– Fixed G729 for arm64 platform;
– Enabled OPUS FEC.
Added method: abtoPhoneCfg.setUseOpusFec(true);
– Fixed possible crash in STUN timer on app start;
– Fixed possible crash in OPUS decode implemntation.