fixes memory overflow with ldd4.3

[SuperUserNameMan]

ldd4.3 Assets.lif contains a large db.lif file which fails to be extracted because of a memory overflow error with python 2.7. this patch make extraction by blocks of 16MB. if the block size is too large, it is divided by 2 till it fits the file size ... (could be improved though)

[JrMasterModelBuilder]

The whole of LIF Extractor really could be improved, but I wouldn't mind merging some patches. I've just got a couple of notes above.

[SuperUserNameMan]

Hi, I'm aware that this patch is more a ugly hack than anything else. Python is not something i'm used to deal with, I just needed the script to work. Feel free to do whatever you want with this PR. And thanks for this script !

[nachtgold]

If its ugly or not - it works 👍

[reditec]

How about finally patching this python file? Plus a documentation about the format would be pretty cool as I want to write a C# tool that does the same as your the python file (not requiring python, tho).