Cherry pick PR 1625, 1715, 1725 to dev-1.x #1726

Merged

lvhan028 merged 3 commits intoopen-mmlab:dev-1.xfrom

lzhangzz:cherry-pick-feb7

Feb 8, 2023

Commits on Feb 7, 2023

[Feature] Support feature map output for mmsegmentation (#1625)

irexyc
authored and
lzhangzz
committed
[Enhancement] Optimize C++ demos (#1715)
lzhangzz
committed
[Fix] Add an option to flip webcam inputs for pose tracker demo (#1725)
lzhangzz
committed