fixed chat window text chat input had gap under it
fixed local video flickering before receiving stream

videoElement.onplaying event listener being used, sometimes a short lag
may be still seen, though it's been very occasional in my tests.
fixed text history extends under remote video slightly
Merge pull request #224 from n1k0/fix-chat-window-chat-input-gap

Fixed chat window text chat input had gap under it
Merge pull request #227 from n1k0/fix-text-history-height

Fixed text history extends under remote video slightly
local video element displayed for video calls only
Merge pull request #225 from n1k0/fix-local-video-flickering

fixed local video flickering before receiving stream