sbar_scoreboard_ improvements. Adds several cvars to control new features such as...

sbar_scoreboard_ improvements. Adds several cvars to control new features such as the ability to control the alpha of the scoreboard, as well as the ability to control the alpha of highlighting and names. Also, make highlighting use GetTeamRGB(pl.team) to retrieve team color, instead of just using a white base. This makes the HUD much more vibrant. I hope this doesn't break anything, let me know if I did something wrong.

NOTE: Someone needs to do cvar hashes now, as I added several.

git-svn-id: svn://svn.icculus.org/nexuiz/trunk@8071 f962a42d-fe04-0410-a3ab-8c8b0445ebaa