Update MinecraftForge to 10.13.0.1160

Signed-off-by: Steven Downer <grinch@outlook.com>
Update README.md

- Changed run configuration information for recent ForgeGradle changes.
- We now support Gradle 1.12+, not just 1.12.
- Update setup instructions.

Signed-off-by: Steven Downer <grinch@outlook.com>