fix: reverted back Z_Free() to free() because it did not fit (caused crash at demo playback) + polished a few more vars (removed useless mallocs)

Signed-off-by: Stephen L. <lrq3000@gmail.com>
fix: svdemo filenames were truncated, now they should have more length to spare

Signed-off-by: Stephen L. <lrq3000@gmail.com>