Revert "Revert 1.25m fuel tanks"

This reverts commit 6519bdcbd1c089873002a4ef40025f2dac9d1921.
Oops, did not commit new MM patch
Added shell script for nix/OS X

Also update readme to describe.
Merge pull request #4 from NathanKell/master

Oops, had wrong MM patch uploaded. Very sorry.