warning infrastructure
added decay warning, closes #847
first draft of trackid implementation
added tests for material and product track and db id bumping
added const signatures as private functions to give compile time failures
python3 removes json encoding keyword arg from dumps func
moved requests and bids mostly into test context in order to clean up memory issues
some final create cleanup
cleaning up inst tests
graphid->state_id, trackid->obj_id, state_id->qual_id
updated comment wording
Merge pull request #860 from scopatz/warn

warning infrastructure
Updated Python version
Updated libxml++ version
Merge pull request #862 from rwcarlsen/json3

python3 removes json encoding keyword arg from dumps func
Merge branch 'dbp2' of https://github.com/gidden/cyclus into gidden-dbp2
Merge branch 'gidden-dbp2' into develop
Merge branch 'trackid' of https://github.com/rwcarlsen/cyclus into rwcarlsen-trackid