add individual state level admin files

[jhelie]

This adds the state level admin files that are generated on the fly by the UI. @gorzell I've noticed that the [Population size] is always equal to the total US pop size (338798532): is it something that should be changed? (for the few files which were already in the repo and that I've simply moved, such as Alaska_admin.txt or Hawaii_admin.txt, the number seems to reflect the actual population of the admin unit).

[weshinsley]

@matt-gretton-dann - this PR fell asleep - I've moved the USA files back into the top level.

@dlaydon - I can't remember whether [Population size] for these state level files should be USA population, or state specific, or whether it matters - it'll be loading the different states out of the same wpop file... (except for the non "mainland-USA" - Alaska, Hawaii, Guam, Virgin Islands US, Puerto Rico, which have their [Population size] set specifically already)

The more I think about it, the more I think this is correct; that the states dug out of the "all-US" wpop file (with the extra schools data) should have the Population Size set to USA, and the others shouldn't - which is what we have... but would be good to confirm

[matt-gretton-dann]

@matt-gretton-dann - this PR fell asleep - I've moved the USA files back into the top level.

@dlaydon - I can't remember whether [Population size] for these state level files should be USA population, or state specific, or whether it matters - it'll be loading the different states out of the same wpop file... (except for the non "mainland-USA" - Alaska, Hawaii, Guam, Virgin Islands US, Puerto Rico, which have their [Population size] set specifically already)

The more I think about it, the more I think this is correct; that the states dug out of the "all-US" wpop file (with the extra schools data) should have the Population Size set to USA, and the others shouldn't - which is what we have... but would be good to confirm

@weshinsley, @dlaydon: How does the [Fix population size at specified value] setting interact with the population size?

I need to update stuff the run_sample.py scripts to understand which wpop files to use for these files.

[matt-gretton-dann]

I have retargeted this to mainline as well (it was targeted at one of my own branches).