FS-11750: don't shrink NACK table (vbw) so drastically (don't drop a frame with every added packet when complete_frames > max_frame_len)

(thanks Sergey KHripchenko)

(affects cum_lost calculation)

(thanks Artem Karukov for finding these)

FS-11635: include received Nacked to the expected packet count.

FS-11631: [core] fix introduced by minor change of behavior, rtcp & ice (FS-11549) -keep rtcp disabled during ICE

FS-11549: don't send the reception report block when we need to send fast feedback (do like Chrome does it, don't confuse peer's stats).
FS-11549: don't send RTCP RR unless we're receiver only.

Needed in Chrome version >= 74 as Chrome dropped support for v1.0:
https://groups.google.com/forum/?utm_medium=email&utm_source=footer#!msg/discuss-webrtc/yr6gbAgWsKo/9X5vQb8kGAAJ

Using old v1.0 DTLS if 1.2 is not available or legacy DTLS
wanted explicitly. To request old DTLS set variable

	<action application="set" data="legacyDTLS=1"/>

Note: requires openssl 1.0.2 or later for DTLS v1.2 support