updated v1.2 symbols
Merge branch 'master' into develop
pyne decay
incs fixes
added pyne_decay.h to cyclus header
pull out decay code download into separate script called by cmake
Merge @scopatz dec branch. Adds pyne decay to Cyclus. Closes #1052.
added simple test to confirm decay works
update composition to use pyne decay and add test for it
Merge pull request #1050 from rwcarlsen/decay-test

added simple test to confirm decay works
lazy decay option and misc cleanups and tweaks

* lazy decay option decays materials every time the Material::comp function is
  called.

* Added ability to call Material::Decay with a negative time argument that
  causes the decay operation to run with the material's context's current
  time.  Throws if the material has a NULL context.