Grown biomes

Added new biome generator, this one looks really close to Vanilla.
Strictly speaking this is valid c++11. However gcc didn't implement it until 4.7 and travis uses 4.6. so either we have to drop support for gcc 4.6 and upgrade the gcc on travis at the start of each build or do this the old way. (Travis are looking at upgrading there gcc as part of an OS upgrade)