chat window layout enhancements

- use table/table-row for the main vertical fluid layout
- remote video now occupies full available width
- WiP
working layout for textchat/texthat/video for small/medium win sizes
added chat layout development file
added offer/establishment switches to chat layout devel html
call now hides depending on call state; updated tests
fixed remote video isn't displayed anymore (platform bug?)
new constraint of 2 lines of text chat text displayed only
full witdh video for full screen detached window (tmp behavior)