Proof-of-capacity whitepaper

Perhaps this should be moved to NebulousLabs/Experimental? Or maybe we should just have a Papers repository...
This is not true.

The outputs of hashing function H follow a normal distribution, the number of events in a specific range follows a poisson distribution, and the distance between the events and a random point follows an exponential distribution.

So the distance between h_i and t should follow an exponential distribution.