v4l2 -  1)update handler 2)source resolution change 3) control of second instance creation
stream - silent call hangup by timeout
ua - ua_hungup_other_calls fix for work with multiple accounts

	modified:   include/baresip.h
	modified:   modules/v4l2/v4l2.c
	modified:   src/config.c
	modified:   src/core.h
	modified:   src/stream.c
	modified:   src/ua.c