cleanup and pep8
add a bunch of different filter properties
Merge pull request #2 from dimagi/cleanup

Cleanup
make xml mappers two-way

push more of the validation and field formatting into the mapper
add .travis.yml
Merge pull request #3 from dimagi/two-way-mapper

Two way mapper
add yaml file exemplifying intended config format
modify config format example
add models for parsing a yaml recipe set