Remove TURN user & password grammar validation (fix #156).
Remove TURN user & password grammar validation (fix #156).

tqcenglish/JsSIP,AaronZhangL/JsSIP,rusekr/JsSIP,DrumTechnologiesLtd/JsSIP,CodeYellowBV/JsSIP,vconsult/JsSIP,dpocock/JsSIP,voxbone/JsSIP