Overlapping blocks in AS

[alaz]

Related to #34. Since you are thinking about enhancements to the structures, I'd like to throw one more suggestion to consider.

Sometimes a large block owned by a hosting provider may contain few smaller blocks designated for other data centers or even other clients who potentially use the addresses for other purposes (i.e. offices, individual customers, whatever). The current structure of datacenters.csv is not a good fit to express such data.

One of the possible workarounds is the format used by Nginx for its geo module. It's possible not only to "include" a block, but also mark a block as "excluded". Here it is the module documentation if you'd want to see it.

[client9]

thanks @alaz I will take a look. These ideas are most helpful.