revert the all-platforms form of CD device stops workaround from r948/r949 ...

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@953 af15c1b1-3010-417e-b628-4374ebc0bcbd
... apply a CD device stops workaround only for linux for now.

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@954 af15c1b1-3010-417e-b628-4374ebc0bcbd
cd_sdl: add back the informative message (was accidentally reverted in r953.)

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@955 af15c1b1-3010-417e-b628-4374ebc0bcbd
AllocBlock: cache index of last used lightmap, start search there

Can speed up map loading by multiple seconds on levels with a lot of lightmaps, at a cost of using slightly more lightmaps (about 5% more).

https://sourceforge.net/p/quakespasm/patches/20/


git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@956 af15c1b1-3010-417e-b628-4374ebc0bcbd
Image_LoadImage: read pixel data in 1K chunks instead of calling getc in a loop

git-svn-id: svn://svn.code.sf.net/p/quakespasm/code/trunk/quakespasm@957 af15c1b1-3010-417e-b628-4374ebc0bcbd