Log Message:
* Version 0.4.11
	* build: export USE_TLS and USE_DTLS flags in re.mk makefile
		 detect sysctl.h and epoll.h for multi-arch platforms
		 dont use libresolv for openbsd
	* main: check that maxfds is less than FD_SETSIZE (for select
                method)
	* dtls: added udp-socket accessor and function to set handlers
	* stun: added support for DTLS-transport
		added doxygen comments
	* tls: added function to set certificate from a string
	* turn: added support for DTLS-transport