Updated elf loader to accept dynamic payload sizes.

[someguythatmods]

The current elf loader implementation has the elf store limited at 2mb, this change allows a payload of any size to come through.

This is done under the assumption that the section header table is at the bottom of the file, and then takes the section header offset + (entry size * number). Im not sure if this is always the case, but it seems to work with all elfs I have tried so far. (with the exception of kstuff, but its a really simple fix to make it work, the section header table offset just needs to be set to the file size.)