Add some log lines into sanity check code for clarity
Add some log lines into sanity check code for clarity

onsip/SIP.js,markandrus/SIP.js,Escaux/SIP.js,onsip/SIP.js,vconsult/JsSIP,josephfrazier/SIP.js,rusekr/JsSIP,joseph-onsip/SIP.js,Voiceworks/SIP.js,ronlobo/SIP.js,AaronZhangL/JsSIP,CodeYellowBV/JsSIP,tqcenglish/JsSIP,DrumTechnologiesLtd/JsSIP,voxbone/JsSIP,dpocock/JsSIP