Improved bloom + experiments with adaptive exposure.

Bloom is heavily inspired by the method described by Jorge Jimenez in his great slides here: http://www.iryoku.com/next-generation-post-processing-in-call-of-duty-advanced-warfare (starts from slide 144)

It depends on what you want from the ore distribution, but I can't think of any particular reason why you can't use a noise map for ores given that you are using one for terrain.