FillRect() is similar enough to memset when blending isn't used, so the
game will take a fast path drawing the roomname background when the
background is opaque.
This is the variable dwgfx.translucentroomname and <translucentroomname>
in unlock.vvv.
This lets you see through the black background of the roomname at the
bottom of the screen, i.e. it makes the roomname background translucent.
So you can see if someone decides to hide pesky spikes there.
The roomname background used to just be a simple SDL_Rect that was drawn
using SDL_FillRect with a color of 0. Unfortunately, it seems that you
cannot use transparent colors with SDL_FillRect, it just defaults to
being fully opaque. However, you CAN draw surfaces with translucency,
which seems like the easiest thing to do. But the first step is to
convert the roomname background to an SDL_Surface.
This replaces the FillRect()s with SDL_BlitSurface() in the three places
roomnames are drawn: in towerrender, in gamerender, and in editorrender.
This fixes a bug where bringing up the pause screen while in a tower
would draw the room you entered BEFORE the tower during the time it took
for the pause screen to be brought up or down.
