Compiling instructions in README.md

Added basic mod info, a link to the minecraftforum.net thread, compiling/build instructions, and the license (taken from the minecraftforum.net thread)
you should remove the ; the correct one liner is:

```
git clone https://github.com/skyboy/MineFactoryReloaded.git && cd MineFactoryReloaded
```

Additionally, surrounding by a gaves or placing it on a new line with 3 graves above and below will make it more readable.