Prediction was rebuilding too much thinglist data

- Stopped player prediction from rebuilding more sector list data then
the player originally had.
Multi-intermission waits for all players + changes

- Added a segment of code that now makes the intermission wait for all
players before advancing, instead of continuing on any player. A "ready
icon" shows to reflect this.

- The Deathmatch intermisson couldn't show the ready icon (because it
just used the ingame scoreboard), so a proper intermission was added,
which reflects the same design as the coop scoreboard.

- The colour column wasted more space then it should have needed, so it
was replaced with player colour backgrounds.

- Slight y offset adjustments to make everything fit in 320x200
properly.
Added wi_autoadvance

- Prevents an absent player from stopping the intermission
fix detection of libglew library on GNU/Linux
Merge branch 'master' of https://github.com/rheit/zdoom
Merge branch 'master' of https://github.com/darealshinji/gzdoom