Merge pull request #10 from synthicity/ipu-rehash

Refactor the IPU calculation of household weights
Rename popgen -> synthpop.
Switch README to restructured text.

[ci skip]
Add version number in __init__.py.
popgen -> synthpop in .travis.yml.
Merge pull request #11 from synthicity/synthpop

Change name from popgen to synthpop
adding synthesizer as the main loop of the program

looks like this is going to be fast - can run ipf for households and population in a small county in about 15 seconds
pep8
synthpop not popsynth!
adding a function to convert to frequency table for use in ipu

still need to work out exactly how all these data gets pass around though
forgot to check pep8
this is a *very* intermediate commit

It should have everything plugged in to the ipu OK, and format the frequency tables appropraitely, but it's not pretty and probably needs a moderate reorg.  Still, I don't want this code just sitting on my laptop.
appears to be running through the ipf and ipu see if we can get the tests running
pep8
pep8
probably don't need this tracts_to_pumas function anymore