winex11.drv: Remove the coloruse == -1 special case. Add X11DRV_DIB_GetColorCount() for computing a bitmap's number of colors.

crypt32: Don't keep a pointer to the lower quality chains when choosing a higher quality one, otherwise they'll get double-freed.

crypt32: Pass reg store's key and memory store to CRYPT_RegReadFromReg, rather than passing a private type.