uvgRTP v2.1.2

This patch release significantly reduces RTCP CPU usage, extends SCL to support NAL units as small as 4 bytes for H264 and 6 bytes for H265/H266 (including start code prefix). These are the smallest sizes reasonable. This release also fixes a bug where separate NAL units with same timestamps are discarded after first.

Fixes

• formats: Support smallest NAL unit sizes in SCL in 5ca3c13
• formats: Don't discard NAL units with same timestamps in c07a8c2
• rtcp: fix socket selection busylooping in rtcp polling by @wowaser in #178

Full Changelog: v2.1.1...v2.1.2